Peptides with antiviral activity, antiviral agents containing the peptides, and methods for manufacturing the antiviral agents.

Abstract

This invention provides a peptide that can bind to the receptor-binding domain (RBD) of SARS-CoV-2, is easily chemically synthesized, has extremely high solubility in ultrapure water or buffer solutions, and is very likely to be realized as a therapeutic agent for COVID-19.

Description

[Technical Field]

[0001] This invention relates to a peptide that interacts with the receptor-binding domain (RBD) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an antiviral agent containing the peptide, and a method for manufacturing the antiviral agent. [Previous Technology]

[0002] Regarding the global pandemic of novel coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2, despite the implementation of global public health measures, its end cannot be predicted. The clinical symptoms induced by SARS-CoV-2 range from asymptomatic infection to severe pneumonia, multiple organ failure, and death.

[0003] Currently, multiple pharmaceutical companies are supplying mRNA vaccines and other vaccines to prevent and treat SARS-CoV-2 infection and the diseases caused by it. However, the SARS-CoV-2 (wild-type SARS-CoV-2) discovered in Wuhan, China, has mutated, resulting in variant SARS-CoV-2, namely, several variant strains represented by the so-called British variant, South African variant, and Brazilian variant, making the end of the novel coronavirus infection more difficult. Here, wild-type SARS-CoV-2 refers to SARS-CoV-2 with the following amino acid sequence constituting the receptor-binding domain (RBD): position 339 is glycine residue, position 371 is serine residue, position 373 is serine residue, position 375 is serine residue, position 376 is threonine residue, position 405 is aspartic acid residue, position 408 is arginine residue, position 41 is aspartic acid residue, position 42 is aspartic acid residue, position 439 is aspartic acid residue, position 42 is aspartic acid residue, position 439 is aspartic acid residue, position 371 is serine residue, position 373 is serine residue, position 375 is serine residue, position 376 is threonine residue, position 405 is aspartic acid residue, position 408 is arginine residue, position 41 is aspartic acid residue, position 42 is aspartic acid residue, position 439 is aspartic acid residue, position 475 is serine residue, position 376 is threonine residue, position 405 is aspartic acid residue, position 408 is arginine residue, position 41 is aspartic acid residue, position 42 is aspartic acid residue, position 439 is aspartic acid residue, position 371 is aspartic acid residue, position 42 is aspartic acid residue, position 439 is aspartic acid residue, position 371 is Position 7 is a lysine residue, position 440 is an aspartic acid residue, position 446 is a glycine residue, position 452 is a leucine residue, position 477 is a serine residue, position 478 is a threonine residue, position 484 is a glutamic acid residue, position 493 is a glutamine residue, position 496 is a glycine residue, position 498 is a glutamine residue, position 501 is an aspartic acid residue, and position 505 is a tyrosine residue. On the other hand, variant SARS-CoV-2 refers to SARS-CoV-2 with at least one variant selected from the group consisting of the following variants: a variant in the amino acid sequence constituting the receptor-binding domain (RBD) where position 339 is an aspartic acid residue, position 371 is a leucine or phenylalanine residue, position 373 is a proline residue, position 375 is a phenylalanine residue, position 376 is an alanine residue, position 405 is an aspartic acid residue, position 408 is a serine residue, and position 417 is an aspartic acid residue. Variations of asparagine residue or threonine residue, variation of position 440 becoming lysine residue, variation of position 446 becoming serine residue, variation of position 452 becoming arginine residue, variation of position 477 becoming asparagine residue, variation of position 478 becoming lysine residue, variation of position 484 becoming lysine residue, variation of glutamine residue or alanine residue, variation of position 493 becoming arginine residue, variation of position 496 becoming serine residue, variation of position 498 becoming arginine residue, variation of position 501 becoming tyrosine residue, and variation of position 505 becoming histidine residue.

[0004] More specifically, as a variant of SARS-CoV-2, examples of SARS-CoV-2 include the following types: those with a variant in which position 501 of the amino acid sequence constituting the receptor-binding domain (RBD) is a tyrosine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 452, 477, 478, 484, 493, 496, 498, and 505 are wild-type (PANGO system name: B.1.1.7, sometimes referred to as the British variant of SARS-CoV-2). Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 can be cited: those with variations in the amino acid sequence constituting the receptor-binding domain (RBD), where position 417 is an aspartic acid residue, position 484 is a lysine residue, and position 501 is a tyrosine residue, and the amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 440, 446, 452, 477, 478, 493, 496, 498, and 505 are wild-type (PANGO systematic name: B.1.351, sometimes referred to as the South African variant SARS-CoV-2). Furthermore, as a variant of SARS-CoV-2, examples of SARS-CoV-2 include those with variations in the amino acid sequence constituting the receptor-binding domain (RBD), where position 417 is a threonine residue, position 484 is a lysine residue, and position 501 is a tyrosine residue. Additionally, amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 440, 446, 452, 477, 478, 493, 496, 498, and 505 are wild-type (PANGO system name: P.1, sometimes referred to as the Brazilian variant SARS-CoV-2).Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 can be cited: those with a variant in which position 452 of the amino acid sequence constituting the receptor-binding domain (RBD) is an arginine residue and position 478 is a lysine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 477, 484, 493, 496, 498, 501, and 505 are wild-type (PANGO systematic name: B.1.617.2, sometimes referred to as Indian variant (δ-type) SARS-CoV-2). Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 can be cited: those with a variant in which position 452 of the amino acid sequence constituting the receptor-binding domain (RBD) is an arginine residue and position 484 is a glutamine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 477, 478, 493, 496, 498, 501, and 505 are wild-type (PANGO systematic name: B.1.617.1, sometimes referred to as Indian variant (κ type) SARS-CoV-2). Furthermore, as variant SARS-CoV-2, the following types of SARS-CoV-2 can be cited: those with the following variations in the amino acid sequence constituting the receptor-binding domain (RBD): position 339 as an aspartic acid residue, position 371 as a leucine residue, position 373 as a proline residue, position 375 as a phenylalanine residue, position 417 as an aspartic acid residue, position 440 as a lysine residue, position 446 as a serine residue, position 477 as an aspartic acid residue, and position 478 as a lysine residue. The variants are lysine residues, alanine residues at position 484, arginine residues at position 493, serine residues at position 496, arginine residues at position 498, tyrosine residues at position 501, and histidine residues at position 505, with amino acid residues at positions 376, 405, 408, and 452 being wild-type (PANGO system name: B.1.1.529 / BA.1, sometimes referred to as the Omecron variant (BA.1 system) SARS-CoV-2).Furthermore, as variants of SARS-CoV-2, the following types of SARS-CoV-2 can be cited: those with the following amino acid sequences constituting the receptor-binding domain (RBD): position 339 as an aspartic acid residue, position 371 as a phenylalanine residue, position 373 as a proline residue, position 375 as a phenylalanine residue, position 376 as an alanine residue, position 405 as an aspartic acid residue, position 408 as a serine residue, position 417 as an aspartic acid residue, and position 440 as a lysine residue. The variants include: a 477th position as an aspartic acid residue, a 478th position as a lysine residue, a 484th position as an alanine residue, a 493rd position as an arginine residue, a 498th position as an arginine residue, a 501st position as a tyrosine residue, and a 505th position as a histamine residue. The amino acid residues at positions 446, 452, and 496 are wild-type (PANGO system name: B.1.1.529 / BA.2, sometimes referred to as the Omecron variant (BA.2 system) SARS-CoV-2).

[0005] Non-Patent Literature 1 discloses a miniature protein of 56 or 64 amino acid residues that exhibits high affinity for the receptor-binding domain (RBD) of wild-type SARS-CoV-2. It has been shown that a specific protein containing 56 amino acid residues (referred to as LCB1) has the highest affinity for the receptor-binding domain (RBD) of wild-type SARS-CoV-2. This miniature protein, referred to as LCB1, has a specific stereostructure in which three helices interact with each other, enabling it to bind to the receptor-binding domain (RBD) of wild-type SARS-CoV-2. [Prior Art Literature] [Non-Patent Literature]

[0006] [Non-Patent Literature 1] L Cao et al., Science 370, 426-431 (2020) [Summary of the Invention]

[0007] [The problem that this invention aims to solve]

[0008] As disclosed in Non-Patent Literature 1, a drug development strategy aims to target the receptor-binding domain (RBD) of SARS-CoV-2 and develop proteins (peptides) that interact with it as therapeutics for COVID-19. However, the proteins disclosed in Non-Patent Literature 1 (specifically, proteins referred to as LCB1 in Non-Patent Literature 1, etc.) are very long sequences for chemical synthesis, and current technology cannot economically synthesize them. Therefore, therapeutics using proteins disclosed in Non-Patent Literature 1 (specifically, proteins referred to as LCB1 in Non-Patent Literature 1, etc.) as the main component are far from sufficient for market launch. In addition, according to the research of the inventors, LCB1, the protein disclosed in Non-Patent Literature 1 that binds most strongly to the receptor-binding domain (RBD) of wild-type SARS-CoV-2, cannot maintain its binding state to the receptor-binding domain (RBD) of variant SARS-CoV-2 such as the UK variant SARS-CoV-2 (B.1.1.7).

[0009] Therefore, the object of the present invention is to provide a peptide, a pharmaceutical composition comprising the peptide, and a method for manufacturing the peptide. The peptide can bind strongly to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 and the receptor-binding domain (RBD) of variant SARS-CoV-2 such as the British variant (B.1.1.7), and is easily chemically synthesized. It also has extremely high solubility in ultrapure water or buffer solutions, making it potentially feasible as a therapeutic agent for COVID-19. [Technical Means for Solving the Problem]

[0010] To achieve the above objectives, the inventors conducted intensive research and successfully developed the following peptide group, thus completing this invention: comprising two helical structures, exhibiting high binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 and the receptor-binding domain (RBD) of variant SARS-CoV-2 such as the British variant (B.1.1.7), maintaining a stable stereostructure, readily chemically synthesizable, and possessing extremely high solubility in ultrapure water or buffer solutions. This invention comprises the following.

[0011] [1] A peptide having a first region comprising a first helix and a second region comprising a second helix in a direction from the N-terminus to the C-terminus, wherein the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequences (a), (b), (c) or (d): (a) amino acid sequence number 1, (b) amino acid sequence number 61, (c) amino acid sequence number 59, or (d) amino acid sequence having more than 80% sequence identity with the amino acid sequences numbered 1, 61 or 59; and the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequences (e), (f) or (g): (e) amino acid sequence number 2, (f) An amino acid sequence with sequence number 57 or more, or (g) an amino acid sequence having more than 80% sequence identity with an amino acid sequence having sequence number 2 or 57, forms a bond between the amino acid residues within 5 residues from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 and the amino acid residues within 5 residues from the C-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, thereby binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0012] [2] The peptide of [1], wherein it has a first region comprising a first helix and a second region comprising a second helix in the direction from the N-terminus to the C-terminus, and the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following (a) or (d1) amino acid sequence, (a) amino acid sequence of sequence number 1, or (d1) amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 1; the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following (e) or (g1) amino acid sequence. (e) An amino acid sequence of sequence number 2, or (g1) an amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 2, forms a bond between the amino acid residues within 5 residues from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 and the amino acid residues within 5 residues from the C-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, thereby binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0013] [3] The peptide of [1], wherein it has a first region comprising a first helix and a second region comprising a second helix in the direction from the N-terminus to the C-terminus, wherein the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequence (b) or (d2): (b) amino acid sequence of sequence number 61, or (d2) amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 61; wherein the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequence (f) or (g2). (f) An amino acid sequence of sequence number 57, or (g2) an amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 57, forms a bond between the amino acid residues within 5 residues from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 and the amino acid residues within 5 residues from the C-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, thereby binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0014] [4] The peptide of [1], wherein it has a first region comprising a first helix and a second region comprising a second helix in the direction from the N-terminus to the C-terminus, wherein the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequence (c) or (db3), (c) the amino acid sequence of sequence number 59, or (d3) an amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 59; wherein the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 comprises the following amino acid sequence (f) or (g2). (f) An amino acid sequence of sequence number 57, or (g2) an amino acid sequence having more than 80% sequence identity with the amino acid sequence of sequence number 57, forms a bond between the amino acid residues within 5 residues from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 and the amino acid residues within 5 residues from the C-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, thereby binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0015] [5] The peptide of any one of [1] to [4], wherein the sequence of the first region above which binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the following amino acid sequences (h), (i), (j), (k) or (l): (h) amino acid sequence number 56, (i) amino acid sequence number 59, (j) amino acid sequence number 61, (k) amino acid sequence number 63, or (l) amino acid sequence number 65, and the sequence of the second region above which binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 57.

[0016] [6] The peptide described in [5], wherein the sequence of the site in the first region above that binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 56.

[0017] [7] The peptide described in [5], wherein the sequence of the site in the first region above that binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 59.

[0018] [8] The peptide described in [5], wherein the sequence of the site in the first region above that binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 61.

[0019] [9] The peptide described in [5], wherein the sequence of the site in the first region above that binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 63.

[0020]

[10] The peptide described in [5], wherein the sequence of the site in the first region above that binds to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 65.

[0021]

[11] The peptide described in any one of [1] to [4] is characterized in that: the amino acid residues within 5 residues on the N-terminal side and the amino acid residues within 5 residues on the C-terminal side are a combination of lysine residues and aspartic acid residues, a combination of lysine residues and glutamic acid residues, a combination of arginine residues and glutamic acid residues, or a combination of arginine residues and aspartic acid residues.

[0022]

[12] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of (d) or (d1) is an amino acid sequence formed by replacing at least one amino acid residue in the group consisting of the amino acid residue at position 1, position 8, position 11 and position 18 of the amino acid sequence of sequence number 1 with other amino acid residues.

[0023]

[13] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of the above (g) or (g1) is an amino acid sequence formed by replacing at least one amino acid residue in the group consisting of the amino acid residue at position 2, the amino acid residue at position 14 and the amino acid residue at position 18 of the amino acid sequence of sequence number 2 with other amino acid residues.

[0024]

[14] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of (d) or (d1) is formed by replacing the arginine residue at position 15 and the glutamic acid residue at position 19 in the amino acid sequence of sequence number 1 with lysine residue and aspartic acid residue, respectively.

[0025]

[15] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of (g) or (g1) is an amino acid sequence in which the glycine residue at position 2 in the amino acid sequence of sequence number 2 is replaced with an alanine residue.

[0026]

[16] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of (g) or (g1) is an amino acid sequence formed by replacing the arginine residue at position 18 in the amino acid sequence of sequence number 2 with a lysine residue.

[0027]

[17] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of (d) or (d1) is an amino acid sequence in which the tyrosine residue at position 10 and the methionine residue at position 13 of the amino acid sequence of sequence number 1 are further retained.

[0028]

[18] The peptide described in [1] or [2] is characterized in that: the amino acid sequence of the above (g) or (g1) is an amino acid sequence in which the histidine residue at position 1, the serine residue at position 9, the aspartic acid residue at position 10 and the tyrosine residue at position 13 of the amino acid sequence of sequence number 2 are further retained.

[0029]

[19] The peptide described in any one of [1] to [4] is characterized in that: the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 and / or the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 consists of 18 to 22 amino acid residues.

[0030]

[20] The peptide described in any one of [1] to [4] is characterized in that it comprises the first region and the second region described above, and the overall sequence length is 39 amino acid residues.

[0031]

[21] The peptide described in any one of [1] to [4] is characterized in that it comprises one amino acid sequence selected from the group consisting of sequence numbers 52 to 55, 58, 60, 62, 64 and 66.

[0032]

[22] A peptide having a first region and a second region in a direction from the N-terminus to the C-terminus, wherein the first region contains an amino acid sequence selected from (h), (i), (j), (k) or (l), (h) amino acid sequence number 56, (i) amino acid sequence number 59, (j) amino acid sequence number 61, (k) amino acid sequence number 63, or (l) amino acid sequence number 65, and wherein the second region contains an amino acid sequence number 57, which binds to the receptor-binding domain (RBD) of SARS-CoV-2.

[0033]

[23] such as the peptide of

[22] , wherein the first region above contains the amino acid sequence of sequence number 56.

[0034]

[24] such as the peptide of

[22] , wherein the first region above contains the amino acid sequence of sequence number 59.

[0035]

[25] such as the peptide of

[22] , wherein the first region above contains the amino acid sequence of sequence number 61.

[0036]

[26] such as the peptide of

[22] , wherein the first region above contains the amino acid sequence of sequence number 63.

[0037]

[27] such as the peptide of

[22] , wherein the first region above contains the amino acid sequence of sequence number 65.

[0038]

[28] A peptide of any one of

[22] to

[27] , wherein the second region above contains the amino acid sequence of sequence number 57.

[0039]

[29] A peptide comprising an amino acid sequence numbered 58 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0040]

[30] A peptide comprising an amino acid sequence numbered 60 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0041]

[31] A peptide comprising an amino acid sequence numbered 62 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0042]

[32] A peptide comprising an amino acid sequence numbered 64 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0043]

[33] A peptide comprising an amino acid sequence numbered 66 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

[0044]

[34] A pharmaceutical composition comprising, as an active ingredient, a peptide as described in any one of [1] to

[33] above.

[0045]

[35] The pharmaceutical composition described above in

[34] contains at least one pharmaceutically permissible carrier.

[0046]

[36] The pharmaceutical composition described above in

[34] or

[35] is used for the treatment of novel coronavirus infection.

[0047]

[37] The peptide described in any of the above [1] to

[33] is used for the treatment of novel coronavirus infection.

[0048]

[38] A treatment for novel coronavirus infection, comprising: administering a therapeutically effective amount of any one of the peptides described above [1] to

[33] to a patient in need of it.

[0049]

[39] Use of a peptide as described in any one of [1] to

[33] above, for use in the manufacture of a pharmaceutical composition for the treatment of novel coronavirus infection.

[0050]

[40] The pharmaceutical composition, peptide, treatment method or use described in any of

[36] to

[39] above is characterized in that the novel coronavirus infection is caused by infection with any of the following SARS-CoV-2: wild-type SARS-CoV-2, wherein the amino acid residue at position 339 of the receptor-binding domain (RBD) is a glycine residue, the amino acid residue at position 371 is a serine residue, the amino acid residue at position 373 is a serine residue, the amino acid residue at position 375 is a serine residue, and the amino acid residue at position 376 is a serine residue. The amino acid residues at positions 405, 408, 417, 440, 446, 452, 477, 478, 484, and 493 are allamine residues. The amino acid residues at positions 496, 407, 408, 408, 409, 410, 409, and 410 are allamine residues. The amino acid residue at position 498 is glycine, the amino acid residue at position 501 is aspartic acid, and the amino acid residue at position 505 is tyrosine. In variant 1 SARS-CoV-2, the amino acid residue at position 501 is tyrosine. In variant 2 SARS-CoV-2, the amino acid residue at position 484 is lysine. In variant 3 SARS-CoV-2, the amino acid residue at position 417 is aspartic acid, and the amino acid residue at position 484 is lysine. In the SARS-CoV-2 variant 4, the amino acid residue at position 501 is tyrosine; in the SARS-CoV-2 variant 5, the amino acid residue at position 417 is threonine, the amino acid residue at position 484 is lysine, and the amino acid residue at position 501 is tyrosine; in the SARS-CoV-2 variant 5, the amino acid residue at position 452 is arginine, and the amino acid residue at position 478 is lysine; in the SARS-CoV-2 variant 6, the amino acid residue at position 452 is arginine, and the amino acid residue at position 484 is glutamine.The 7th variant of SARS-CoV-2 has the following amino acid residues: aspartic acid at position 339, leucine at position 371, proline at position 373, phenylalanine at position 375, aspartic acid at position 417, lysine at position 440, serine at position 446, and so on. The amino acid residues at positions 476, 48, 493, 496, 498, 501, and 505 are all amino acid residues; SARS-8 variant... CoV-2 has the following amino acid residues: aspartic acid at position 339, phenylalanine at position 371, proline at position 373, phenylalanine at position 375, alanine at position 376, aspartic acid at position 405, serine at position 408, and aspartic acid at position 417. The amino acid residues at positions 440, 477, 478, 484, 493, 498, 501, and 505 are all amino acid residues.

[0051]

[41] The pharmaceutical composition for treating novel coronavirus infection as described in

[36] is characterized by being an aqueous solution containing the above-mentioned peptide. This specification contains the disclosures of Japanese Patent Application Nos. 2021-113006, 2021-145370, and 2022-103949, which form the basis of this priority claim. [Effects of the Invention]

[0052] The peptide of the present invention has the following characteristics: excellent binding ability to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 or mutant SARS-CoV-2, easy chemical synthesis, and extremely high solubility in ultrapure water or buffer solutions, making it highly likely to be realized as a therapeutic agent for COVID-19. Therefore, the peptide of the present invention can prevent infection of cells by wild-type SARS-CoV-2 and mutant SARS-CoV-2 in vivo.

[0053] Furthermore, the novel coronavirus infection treatment drug of the present invention uses the following peptide as its active ingredient. This peptide has excellent binding ability to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 or mutant SARS-CoV-2, is easy to chemically synthesize, and has extremely high solubility in ultrapure water or buffer solutions, making it highly likely to be realized as a treatment drug for COVID-19. Therefore, the novel coronavirus infection treatment drug of the present invention can prevent wild-type SARS-CoV-2 and mutant SARS-CoV-2 from infecting cells in vivo, and thus can be expected to be an effective treatment drug against COVID-19.

Implementation Method

[0055] Hereinafter, the invention will be described in detail. The peptide of the present invention can bind to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 or mutant SARS-CoV-2. Thereby, the peptide of the present invention can inhibit the binding of ACE2 (angiotensin-converting enzyme 2) expressed on the cell to the receptor-binding domain (RBD) of SARS-CoV-2, thereby preventing SARS-CoV-2 from infecting the cell. For wild-type SARS-CoV-2, the structural analysis results of the Spike(S) protein present on the surface of the virus are shown in Wrapp, D. et al. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Science 367, 1260-1263 (2020). It is known that the S protein forms a trimer and has a basic amino acid sequence that can be cleaved by furin, a protein-degrading enzyme of the host. The S protein is cleaved by furin protease into an S1 subunit responsible for receptor binding and an S2 subunit responsible for membrane fusion. The peptide of this invention can bind to the receptor-binding domain (RBD) located in the S1 subunit. In this invention, "receptor-binding domain (RBD)" refers to the receptor-binding domain (RBD) located in the S1 subunit of the Spike protein.

[0056] The peptide of the present invention has two helical structures (for convenience, the N-terminal side is referred to as the first helix, and the C-terminal side as the second helix). The peptide of the present invention comprises a region having the first helix on the N-terminal side (for convenience, referred to as the first region) and a region having the second helix on the C-terminal side (for convenience, referred to as the second region), and bonds are formed between amino acid residues within 5 residues on the N-terminal side of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 and amino acid residues within 5 residues on the C-terminal side of the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2. As described above, a feature of the peptide of the present invention is that the desired three-dimensional structure can be maintained by the bonds formed between the amino acid residues within 5 residues on the N-terminal side of the first region and the amino acid residues within 5 residues on the C-terminal side of the second region. In this invention, the bond between the amino acid residues within 5 residues on the N-terminal side included in the first region and the amino acid residues within 5 residues on the C-terminal side included in the second region includes a salt bridge or a hydrogen bond. Hereinafter, the bond is sometimes specifically referred to as a salt bridge or a hydrogen bond, but the salt bridge or hydrogen bond can be referred to as a bond.

[0057] Furthermore, "amino acid residues within 5 residues from the N-terminus" refers to amino acid residues located between 1 and 5 amino acid residues counting from the N-terminus, and does not mean that the position of the amino acid residues participating in the formation of the above-mentioned bonds is limited to the N-terminus. Similarly, "amino acid residues within 5 residues from the C-terminus" refers to amino acid residues located between 1 and 5 amino acid residues counting from the C-terminus, and does not mean that the position of the amino acid residues participating in the formation of the above-mentioned bonds is limited to the C-terminus.

[0058] Furthermore, one feature of the peptide of the present invention is that: by introducing hydrophilic amino acid residues (specifically, for example, the arginine residue at position 15 and the glutamic acid residue at position 19 of sequence number 1) into the first helix, the helical structure is stabilized and hydrophilized along with the formation of salt bridges by these residues, thereby obtaining extremely high solubility in ultrapure water or buffer solution.

[0059] Furthermore, in the peptide of the present invention, the first region and the second region respectively have amino acid sequences that can bind to the receptor-binding domain (RBD) of SARS-CoV-2 in the state of adopting the above-described stereostructure, which can be defined by each amino acid sequence. Specifically, the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequences (a), (b), (c) or (d): (a) Amino acid sequence of sequence number 1 (b) Amino acid sequence of sequence number 61 (c) Amino acid sequence of sequence number 59 (d) Amino acid sequence that has more than 80% sequence identity with the amino acid sequences of sequence numbers 1, 61 or 59. Furthermore, the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequences (e), (f) or (g). (e) The amino acid sequence of sequence number 2 (f) The amino acid sequence of sequence number 57 (g) An amino acid sequence that has more than 80% sequence identity with the amino acid sequence of sequence number 2 or 57.

[0060] Furthermore, the sequence of the binding site of the first region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (a) or (d1): (a) An amino acid sequence (d1) having more than 80% sequence identity with the amino acid sequence of sequence number 1. Also, the sequence of the binding site of the second region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (e) or (g1): (e) An amino acid sequence (g1) having more than 80% sequence identity with the amino acid sequence of sequence number 2.

[0061] Furthermore, the sequence of the binding site of the first region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (b) or (d2). (b) An amino acid sequence (d2) having more than 80% sequence identity with the amino acid sequence of sequence number 61. Also, the sequence of the binding site of the second region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (f) or (g2). (f) An amino acid sequence (g2) having more than 80% sequence identity with the amino acid sequence of sequence number 57.

[0062] Furthermore, the sequence of the binding site of the first region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (c) or (d3). (c) An amino acid sequence (d3) having more than 80% sequence identity with the amino acid sequence of sequence number 59. Also, the sequence of the binding site of the second region to the receptor-binding domain (RBD) of SARS-CoV-2 can be defined as the following amino acid sequence (f) or (g2). (f) An amino acid sequence (g2) having more than 80% sequence identity with the amino acid sequence of sequence number 57.

[0063] The amino acid sequence of (a), (b), or (c) of the first region is specified to have a lysine residue (the second amino acid residue from the N-terminus in sequence number 1, 59, or 61), and the amino acid sequence of (e) or (f) of the second region is specified to have an aspartic acid residue (the first amino acid residue from the C-terminus in sequence number 2 or 57). The peptides of the present invention specified in sequence number 1, 59, or 61 and sequence number 2 or 57 can be stabilized in the desired stereostructure by the formation of the aforementioned salt bridge between the lysine residue and the aspartic acid residue.

[0064] The salt bridge formed between the first region and the second region is not limited to being formed by the aforementioned lysine residues and aspartic acid residues. For example, even if the amino acid residue at the second position from the N-terminus in sequence number 1, 59, or 61 is an aspartic acid residue, and the amino acid residue at the first position from the C-terminus in sequence number 2 or 57 is a lysine residue, a salt bridge can still be formed between these aspartic acid residues and lysine residues to stabilize the desired stereostructure.

[0065] Furthermore, the combination of amino acid residues forming the salt bridge is not limited to the combination of lysine residues and aspartic acid residues described above. Examples include combinations of lysine residues and glutamic acid residues, combinations of arginine residues and glutamic acid residues, and combinations of arginine residues and aspartic acid residues. That is, as an example, even if the second position from the N-terminus in sequence number 1, 59, or 61 is set as an arginine residue, and the first position from the C-terminus in sequence number 2 or 57 is set as a glutamic acid residue, a salt bridge can still be formed between these arginine residues and glutamic acid residues, thereby stabilizing the desired stereostructure. Moreover, when a salt bridge is formed between arginine residues and glutamic acid residues, the second position from the N-terminus in sequence number 1, 59, or 61 can also be set as a glutamic acid residue, and the first position from the C-terminus in sequence number 2 or 57 can be set as an arginine residue.

[0066] The amino acid sequences specified above (d), (d1), (d2) or (d3) are amino acid sequences that bind to the receptor-binding domain (RBD) of SARS-CoV-2. As long as the amino acid residues involved in forming the above-mentioned bond between the first region and the second region are preserved, they can be set as amino acid sequences that have 80% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more or more or more sequence identity with the amino acid sequences of sequence numbers 1, 59 or 61.

[0067] Furthermore, the amino acid sequences (d), (d1), (d2), or (d3) mentioned above are defined as amino acid sequences at the site of binding to the receptor-binding domain (RBD) of SARS-CoV-2. As long as the amino acid residues involved in forming the aforementioned bond between the first and second regions are preserved, they can be defined as amino acid sequences formed by substituting 1 to 4 amino acid residues from the amino acid sequences of sequence numbers 1, 59, or 61. Moreover, an amino acid sequence formed by substituting 1 amino acid residue from the amino acid sequences of sequence numbers 1, 59, or 61 has 95% sequence identity with the amino acid sequences of sequence numbers 1, 59, or 61. An amino acid sequence formed by substituting 2, 3, or 4 amino acid residues from the amino acid sequences of sequence numbers 1, 59, or 61 has 90%, 85%, or 80% sequence identity with the amino acid sequences of sequence numbers 1, 59, or 61, respectively.

[0068] When replacing 1 to 4 amino acid residues with the amino acid sequence of sequence number 1, 59 or 61, there is no particular limitation on the amino acid residues to be replaced, and the group consisting of the amino acid residue at position 1 (aspartic acid residue), the amino acid residue at position 8 (lysine residue), the amino acid residue at position 11 (glutamic acid residue) and the amino acid residue at position 18 (glutamic acid residue) in the amino acid sequence of sequence number 1, 59 or 61 can be freely selected. The amino acid residues at positions 1 (aspartic acid residue), 8 (lysine residue), 11 (glutamic acid residue), and 18 (glutamic acid residue) in the amino acid sequences numbered 1, 59, or 61 contribute to the stabilization of the helical structure, but have minimal interaction with the receptor-binding domain (RBD) in SARS-CoV-2, and can therefore be replaced with amino acid residues of similar properties.

[0069] The aspartic acid residue at position 1 in sequence numbers 1, 59, or 61 is not particularly limited and can be replaced with an aspartic acid residue or a glutamic acid residue. Aspartic acid and aspartic acid have the property of starting with an N-cap helix and have similar properties. Furthermore, aspartic acid and glutamic acid are both acidic amino acids and have similar properties. Therefore, even if the aspartic acid residue at position 1 in sequence numbers 1, 59, or 61 is replaced with an aspartic acid residue or a glutamic acid residue, the effect on the structure of the first helix or the interaction with the receptor-binding domain (RBD) in SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained.

[0070] Furthermore, the lysine residue at position 8 in sequence numbers 1, 59, or 61 is not particularly limited and can be replaced with an arginine residue or a histidine residue. Lysine, arginine, and histidine are basic amino acids and have similar properties. Therefore, even if the lysine residue at position 8 in sequence numbers 1, 59, or 61 is replaced with an arginine residue or a histidine residue, the effect on the structure of the first helix or the interaction with the receptor-binding domain (RBD) of SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained. In particular, lysine and arginine are similar in that they do not have an aromatic ring, so when the lysine residue at position 8 is replaced with an arginine residue, the effect on the structure of the first helix or the interaction with the receptor-binding domain (RBD) of SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained to a high degree.

[0071] Furthermore, the glutamic acid residues at positions 11 and 18 in sequence numbers 1, 59, or 61 are not particularly limited and can be replaced with aspartic acid residues. Glutamic acid and aspartic acid are both acidic amino acids and have similar properties. Therefore, even if the glutamic acid residues at positions 11 and / or 18 in sequence numbers 1, 59, or 61 are replaced with aspartic acid residues, the impact on the structure of the first helix or on the interaction with the receptor-binding domain (RBD) in SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained.

[0072] The amino acid sequence specified above (g), (g1) or (g2) is an amino acid sequence that binds to the receptor-binding domain (RBD) of SARS-CoV-2. As long as the amino acid residues involved in forming the above-mentioned bond between the first region and the second region are preserved, it can be set as an amino acid sequence that has 80% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more or more or more sequence identity with the amino acid sequence of sequence number 2 or 57.

[0073] Furthermore, the amino acid sequences specified above (g), (g1), or (g2) are amino acid sequences at the site of binding to the receptor-binding domain (RBD) of SARS-CoV-2. As long as the amino acid residues involved in forming the aforementioned bond between the first and second regions are preserved, they can be defined as amino acid sequences formed by substituting 1 to 3 amino acid residues from the amino acid sequence of sequence number 2 or 57. Moreover, an amino acid sequence formed by substituting 1 amino acid residue from the amino acid sequence of sequence number 2 or 57 has 94.7% sequence identity with the amino acid sequence of sequence number 2 or 57. An amino acid sequence formed by substituting 2 or 3 amino acid residues from the amino acid sequence of sequence number 2 or 57 has 89.5% or 84.2% sequence identity with the amino acid sequence of sequence number 2 or 57, respectively.

[0074] When replacing 1 to 3 amino acid residues in the amino acid sequence of sequence number 2 or 57, there is no particular limitation on the amino acid residues to be replaced, and the group consisting of the amino acid residue at position 2 (glycine residue), the amino acid residue at position 14 (glutamic acid residue), and the amino acid residue at position 18 (arginine residue) in the amino acid sequence of sequence number 2 or 57 can be freely selected.

[0075] The glycine residue at position 2 in sequence number 2 or 57 can be replaced with an alanine residue. The glycine residue at position 2 in sequence number 2 or 57 is the optimal amino acid residue for the entire receptor-binding domain (RBD) where the aspartic acid residue at position 501 is mutated to a tyrosine residue. However, by replacing it with an alanine residue, it will bind more strongly to the receptor-binding domain (RBD) in wild-type SARS-CoV-2.

[0076] In the peptide of the present invention, the amino acid residue at position 1 of sequence number 2 or 57 is preferably a histidine residue. When the amino acid residue at position 1 of sequence number 2 or 57 is a histidine residue, it interacts with the amino acid residue at position 19 of sequence number 1, 59, or 61, such as a glutamic acid residue, thereby contributing to structural stabilization. Furthermore, this histidine residue contributes to the stabilization of the helical bundle structure.

[0077] Furthermore, the glutamic acid residue at position 14 in sequence number 2 or 57 is not particularly limited and can be replaced with an aspartic acid residue. Both glutamic acid and aspartic acid are acidic amino acids and have similar properties. Therefore, even if the glutamic acid residue at position 14 in sequence number 2 or 57 is replaced with an aspartic acid residue, the impact on the structure of the second helix or on the interaction with the receptor-binding domain (RBD) in SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained.

[0078] Furthermore, the arginine residue at position 18 in sequence number 2 or 57 is not particularly limited and can be replaced with a lysine residue or a histidine residue. Arginine, lysine, and histidine are basic amino acids and have similar properties. Therefore, even if the arginine residue at position 18 in sequence number 2 or 57 is replaced with a lysine residue or a histidine residue, the effect on the structure of the second helix or the interaction with the receptor-binding domain (RBD) of SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained. In particular, lysine and arginine are similar in that they do not have an aromatic ring, so when the arginine residue at position 18 is replaced with a lysine residue, the effect on the structure of the second helix or the interaction with the receptor-binding domain (RBD) of SARS-CoV-2 is minimal, and the function of the peptide of the present invention can be maintained to a high degree.

[0079] As described above, examples have been given of amino acid residues that can be replaced for the sequences of the first region bound to the receptor-binding domain (RBD) of SARS-CoV-2 and the second region bound to the receptor-binding domain (RBD) of SARS-CoV-2 as defined by (d), (d1), (d2) or (d3) and (g), (g1) or (g2). However, the sequences of the first region bound to the receptor-binding domain (RBD) of SARS-CoV-2 and the second region bound to the receptor-binding domain (RBD) of SARS-CoV-2 are not limited to the above description.

[0080] The sequence of the first region of the peptide of the present invention, which binds to the receptor-binding domain (RBD) of SARS-CoV-2, can be an amino acid sequence formed by replacing amino acid residues other than the aspartic acid residue at position 1, lysine residue at position 8, glutamic acid residue at position 11, and glutamic acid residue at position 18 in sequence numbers 1, 59, or 61 with other amino acid residues. Alternatively, it can be an amino acid sequence formed by deleting and / or inserting 1 to 4 amino acid residues in the amino acid sequence of sequence numbers 1, 59, or 61. That is, the sequence of the first region, which binds to the receptor-binding domain (RBD) of SARS-CoV-2, is not limited to sequence numbers 1, 59, or 61 containing 20 amino acid residues, but can be an amino acid sequence containing 16 to 24 amino acid residues, preferably 18 to 22 amino acid residues.

[0081] Furthermore, the sequence of the second region of the peptide of the present invention that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can be an amino acid sequence formed by replacing amino acid residues other than the glycine residue at position 2, the glutamic acid residue at position 14, and the arginine residue at position 18 in sequence number 2 or 57 with other amino acid residues, or it can be an amino acid sequence formed by deleting and / or inserting 1 to 3 amino acid residues in the amino acid sequence of sequence number 2 or 57. That is, the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 is not limited to sequence number 2 or 57 containing 19 amino acid residues, and can be set to an amino acid sequence containing 16 to 23 amino acid residues, preferably 18 to 22 amino acid residues.

[0082] The peptide of the present invention may contain 36 to 44 amino acid residues in the first region and the second region combined, but preferably 39 amino acid residues in total. By setting the first region and the second region to a total of 39 amino acid residues, a salt bridge can be formed between the lysine residue on the N-terminal side of the first region and the aspartic acid residue on the C-terminal side of the second region, and it becomes a size suitable for binding to the receptor-binding domain (RBD) in SARS-CoV-2.

[0083] As described above, even if the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 contains an amino acid sequence different from sequence number 1, 59 or 61, and the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 contains an amino acid sequence different from sequence number 2 or 57, the desired three-dimensional structure can still be maintained by forming a salt bridge between the amino acid residues within 5 residues from the N-terminus of the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 (the lysine residue at the second position from the N-terminus in sequence number 1) and the amino acid residues within 5 residues from the C-terminus of the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 (the aspartic acid residue at the first position from the C-terminus in sequence number 2). Therefore, even if the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 contains an amino acid sequence different from sequence number 1, 59, or 61, and the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 contains an amino acid sequence different from sequence number 2 or 57, the peptide of the present invention can still bind to the receptor-binding domain (RBD) of SARS-CoV-2 in the same way.

[0084] Here, the functions of each amino acid residue are summarized in Tables 1 and 2 below, regarding the first region containing the amino acid sequence of sequence number 1 and the second region containing the amino acid sequence of sequence number 2.

[0085] [Table 1] Area 1 ① D It is responsible for initiating the spiral structure. It functions as the N-cap. ② K It forms salt bridges with ㊴D and hydrogen bonds with ㉟F and ㊳R, which helps stabilize the helical bundle structure. ③ E It forms hydrogen bonds with S4T7 of RBD (except for the Omecron variant). ④ W It helps stabilize the helical bundle structure. ⑤ I The hydrophobic interaction with ⑨I contributes to the stabilization of the helical structure. The hydrophobic interaction with ㉟F contributes to the stabilization of the helical bundle structure. ⑥ L It forms hydrophobic interactions with A475 and Y489 of RBD. It also forms hydrophobic interactions with ㉜I, ㉟F, and ㊱M, which contribute to the stabilization of the helical bundle structure. ⑦ Q It forms hydrogen bonds with Y489 of RBD. ⑧ K The salt bridge formed with ⑪E helps stabilize the helical structure. 9 I It forms hydrophobic interactions with ⑤I, which contributes to the stabilization of the helical structure. It also forms hydrophobic interactions with ㉘V, ㉛L, ㉜I, and ㉟F, which contribute to the stabilization of the helical bundle structure. ⑩ Y It forms hydrophobic interactions with Y489 and F456 of RBD. The amino acid residue at this position is optimally Y, which is the site required for binding with RBD. It also forms hydrophobic interactions with ⑬M, contributing to the stabilization of the helical structure. ⑪ E The formation of salt bridges with ⑧K helps stabilize the helical structure. ⑫ I The hydrophobic interaction with ⑯L contributes to the stabilization of the helical structure. The hydrophobic interaction with ≘V contributes to the stabilization of the helical bundle structure. ⑬ M It forms a hydrophobic interaction with L455 of RBD. It also forms a hydrophobic interaction with ⑩Y, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ㉘V and ㉜I, and hydrogen bonds with ㉕S, which contribute to the stabilization of the helical bundle structure. For the desired binding site with RBD, the amino acid residue at this position is optimally M. ⑭ R It forms hydrogen bonds with Q493 of RBD. ⑮ R The salt bridge formed with ⑱E and ⑲E helps stabilize the helical structure. 16 L It forms a hydrophobic interaction with ⑫I, which helps stabilize the helical structure. It also forms a hydrophobic interaction with ㉔A and ㉘V, which helps stabilize the helical bundle structure. ⑰ D It forms a hydrogen bond with Q493 of RBD (except for the Omecron variant). For this site, which is crucial for binding with RBD, the amino acid residue at this position is optimally D. 18 E The salt bridge formed with ⑮R helps stabilize the helical structure. 19 E The salt bridge formed with ⑮R helps stabilize the helical structure. The salt bridge formed with ㉑H helps stabilize the corner structure. ⑳ G It forms a hydrogen bond with Q498 of RBD. This is a crucial site for the formation of the left-hand turn structure, and the amino acid residue at this position must be G.

[0086] [Table 2] Area 2 ㉑ H The formation of a salt bridge with ⑲E contributes to the stabilization of the turn structure. This is a crucial site for the stabilization of the helical bundle structure, and the amino acid residue at this position is preferably H. 20 G When combined with an RBD that has an N501Y variant, it is responsible for creating the space required to contain the N501Y. 23 E It forms hydrogen bonds with G502 of RBD. 26 A The hydrophobic interaction with ⑯L helps stabilize the helical bundle structure. 20 S The formation of hydrogen bonds with ⑬M contributes to the stabilization of the helical bundle structure. 2 L It forms hydrophobic interactions with RBD Y495 and Y505 (except for the Omecron type). 27 R The salt bridge formed with 23E helps stabilize the helical structure. 20 V Hydrophobic interactions with ≛L contribute to the stabilization of the helical structure. Hydrophobic interactions with ⑨I, ⑫I, ⑬M, and ⑯L also contribute to the stabilization of the helical bundle structure. ㉙ S It forms hydrogen bonds with Y453 of RBD. ㉚ D It forms a salt bridge with R403 and K417 of RBD. This is a relatively important part for bonding with RBD. ㉛ L The hydrophobic interaction with V (≘V) contributes to the stabilization of the helical structure. The hydrophobic interaction with I (⑨I) contributes to the stabilization of the helical bundle structure. ㉜ I It forms hydrophobic interactions with L455 and F456 of RBD. It also forms hydrophobic interactions with ㊱M, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ⑥L, ⑨I, and ⑬M, which contribute to the stabilization of the helical bundle structure. ㉝ Y It forms hydrogen bonds with D420 of RBD. ㉞ E It can be any amino acid residue, but E is preferred in order to maintain the high hydrophilicity of the peptide. ㉟ F It forms hydrogen bonds with ②K. It also forms hydrophobic interactions with ⑤I, ⑥L, and ⑨I. These interactions contribute to the stabilization of the helical bundle structure. ㊱ M It forms hydrophobic interactions with F456 and Y473 of RBD. It also forms hydrophobic interactions with ㉜I, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ⑥L, which contributes to the stabilization of the helical bundle structure. ㊲ K It forms a salt bridge with D420 of RBD and hydrogen bonds with Y421 and N460. ㊳ R The formation of hydrogen bonds with ②K contributes to the stabilization of the helical bundle structure. ㊴ D The salt bridge formed with ②K helps stabilize the helical bundle structure.

[0087] Here, the functions of each amino acid residue are summarized in Tables 3 and 4 below, regarding the first region containing the amino acid sequence of sequence number 59 and the second region containing the amino acid sequence of sequence number 57.

[0088] [Table 3] Area 1 ① D It is responsible for initiating the spiral structure. It functions as the N-cap. ② K It forms salt bridges with ㊴D and hydrogen bonds with ㉟F and ㊳R, which helps stabilize the helical bundle structure. ③ L It interacts with F486, which is important for the binding of RBD and ACE2, thereby enhancing the binding ability with RBD. ④ W It helps stabilize the helical bundle structure. ⑤ I The hydrophobic interaction with ⑨I contributes to the stabilization of the helical structure. The hydrophobic interaction with ㉟F contributes to the stabilization of the helical bundle structure. ⑥ L It forms hydrophobic interactions with A475 and Y489 of RBD. It also forms hydrophobic interactions with ㉜I, ㉟F, and ㊱M, which contribute to the stabilization of the helical bundle structure. ⑦ Q It forms hydrogen bonds with Y489 of RBD. ⑧ K The salt bridge formed with ⑪E helps stabilize the helical structure. 9 I It forms hydrophobic interactions with ⑤I, which contributes to the stabilization of the helical structure. It also forms hydrophobic interactions with ㉘V, ㉛L, ㉜I, and ㉟F, which contribute to the stabilization of the helical bundle structure. ⑩ Y It forms hydrophobic interactions with Y489 and F456 of RBD. The amino acid residue at this position is preferably Y, which is the site required for binding with RBD. It also forms hydrophobic interactions with ⑬M, which contributes to the stabilization of the helical structure. ⑪ E The formation of salt bridges with ⑧K helps stabilize the helical structure. ⑫ I The hydrophobic interaction with ⑯L contributes to the stabilization of the helical structure. The hydrophobic interaction with ≘V contributes to the stabilization of the helical bundle structure. ⑬ M It forms a hydrophobic interaction with L455 of RBD. It also forms a hydrophobic interaction with ⑩Y, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ㉘V and ㉜I, and hydrogen bonds with ㉕S, which contribute to the stabilization of the helical bundle structure. For the desired binding site with RBD, the amino acid residue at this position is optimally M. ⑭ V For sites where binding with RBD is more important, the amino acid residue at that position is preferably V. ⑮ R The salt bridge formed with ⑱E and ⑲E helps stabilize the helical structure. 16 L It forms a hydrophobic interaction with ⑫I, which helps stabilize the helical structure. It also forms a hydrophobic interaction with ㉔A and ㉘V, which helps stabilize the helical bundle structure. ⑰ D It forms a hydrogen bond with Q493 of RBD (except for the Omecron variant). For this site, which is crucial for binding with RBD, the amino acid residue at this position is optimally D. 18 E The salt bridge formed with ⑮R helps stabilize the helical structure. 19 E The salt bridge formed with ⑮R helps stabilize the helical structure. The salt bridge formed with ㉑H helps stabilize the corner structure. ⑳ G It forms a hydrogen bond with Q498 of RBD. This is a crucial site for the formation of the left-hand turn structure, and the amino acid residue at this position must be G.

[0089] [Table 4] Area 2 ㉑ H The formation of a salt bridge with ⑲E contributes to the stabilization of the turn structure. This is a crucial site for the stabilization of the helical bundle structure, and the amino acid residue at this position is preferably H. 20 G When combined with an RBD that has an N501Y variant, it is responsible for creating the space required to contain the N501Y. 23 E It forms hydrogen bonds with G502 of RBD. 26 A The hydrophobic interaction with ⑯L helps stabilize the helical bundle structure. 20 S The formation of hydrogen bonds with ⑬M contributes to the stabilization of the helical bundle structure. 2 L It forms hydrophobic interactions with RBD Y495 and Y505 (except for the Omecron type). 27 M This is a site that is particularly important for binding with the Y505 (excluding the omega-jung type) or H505 (omega-jung type) of the RBD. Furthermore, this is a site that is particularly important for stabilizing the helical bundle structure, and the amino acid residue at this position is preferably M. 20 V Hydrophobic interactions with ≛L contribute to the stabilization of the helical structure. Hydrophobic interactions with ⑨I, ⑫I, ⑬M, and ⑯L also contribute to the stabilization of the helical bundle structure. ㉙ S It forms hydrogen bonds with Y453 of RBD. ㉚ D It forms a salt bridge with R403 and K417 of RBD. This is a relatively important part for bonding with RBD. ㉛ L The hydrophobic interaction with V (≘V) contributes to the stabilization of the helical structure. The hydrophobic interaction with I (⑨I) contributes to the stabilization of the helical bundle structure. ㉜ I It forms hydrophobic interactions with L455 and F456 of RBD. It also forms hydrophobic interactions with ㊱M, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ⑥L, ⑨I, and ⑬M, which contribute to the stabilization of the helical bundle structure. ㉝ Y It forms hydrogen bonds with D420 of RBD. ㉞ E It can be any amino acid residue, but E is preferred in order to maintain the high hydrophilicity of the peptide. ㉟ F It forms hydrogen bonds with ②K. It also forms hydrophobic interactions with ⑤I, ⑥L, and ⑨I. These interactions contribute to the stabilization of the helical bundle structure. ㊱ M It forms hydrophobic interactions with F456 and Y473 of RBD. It also forms hydrophobic interactions with ㉜I, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ⑥L, which contributes to the stabilization of the helical bundle structure. ㊲ K It forms a salt bridge with D420 of RBD and hydrogen bonds with Y421 and N460. ㊳ R The formation of hydrogen bonds with ②K contributes to the stabilization of the helical bundle structure. ㊴ D The salt bridge formed with ②K helps stabilize the helical bundle structure.

[0090] Here, regarding the first region containing the amino acid sequence number 61, the functions of each amino acid residue are summarized in Table 5 below.

[0091] Table 5 Area 1 ① D It is responsible for initiating the spiral structure. It functions as the N-cap. ② K It forms salt bridges with ㊴D and hydrogen bonds with ㉟F and ㊳R, which helps stabilize the helical bundle structure. ③ E It forms hydrogen bonds with RBD S477 (except for the Omecron variant) or N477 (Omecron variant). ④ W It helps stabilize the helical bundle structure. ⑤ I The hydrophobic interaction with ⑨I contributes to the stabilization of the helical structure. The hydrophobic interaction with ㉟F contributes to the stabilization of the helical bundle structure. ⑥ L It forms hydrophobic interactions with A475 and Y489 of RBD. It also forms hydrophobic interactions with ㉜I, ㉟F, and ㊱M, which contribute to the stabilization of the helical bundle structure. ⑦ Y It interacts with F486, which is important for the binding of RBD and ACE2, thereby enhancing the binding ability with RBD. ⑧ K The salt bridge formed with ⑪E helps stabilize the helical structure. 9 I It forms hydrophobic interactions with ⑤I, which contributes to the stabilization of the helical structure. It also forms hydrophobic interactions with ㉘V, ㉛L, ㉜I, and ㉟F, which contribute to the stabilization of the helical bundle structure. ⑩ Y It forms a hydrophobic interaction with Y489 and F456 of RBD. The amino acid residue at this position is optimally Y, which is the site required for binding with RBD. ⑪ E The salt bridge formed with ⑧K and ⑮R helps stabilize the helical structure. ⑫ I The hydrophobic interaction with ⑯L contributes to the stabilization of the helical structure. The hydrophobic interaction with ≘V contributes to the stabilization of the helical bundle structure. ⑬ M It forms a hydrophobic interaction with L455 of RBD. It also forms a hydrophobic interaction with ⑩Y, which contributes to the stabilization of the helical structure. Furthermore, it forms hydrophobic interactions with ㉘V and ㉜I, and hydrogen bonds with ㉕S, which contribute to the stabilization of the helical bundle structure. For the desired binding site with RBD, the amino acid residue at this position is optimally M. ⑭ V For sites where binding with RBD is more important, the amino acid residue at that position is preferably V. ⑮ R The salt bridges formed with ⑪E, ⑱E, and ⑲E contribute to the stabilization of the helical structure. 16 L It forms a hydrophobic interaction with ⑫I, which helps stabilize the helical structure. It also forms a hydrophobic interaction with ㉔A and ㉘V, which helps stabilize the helical bundle structure. ⑰ D It forms hydrogen bonds with Q493 of RBD (except for the Omecron variant). It also forms salt bridges with R493 (Omecron variant). For this site, which is crucial for binding with RBD, the amino acid residue at this position is optimally D. The formation of salt bridges with ⑮R contributes to the stabilization of the helical bundle structure. 18 E The salt bridge formed with ⑮R helps stabilize the helical structure. 19 E The salt bridge formed with ⑮R helps stabilize the helical structure. The salt bridge formed with ㉑H helps stabilize the corner structure. ⑳ G It forms a hydrogen bond with Q498 of RBD. This is a crucial site for the formation of the left-hand turn structure, and the amino acid residue at this position must be G.

[0092] Furthermore, in the table above, for example, the notation "S477 of RBD" refers to the 477th serine residue in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2 (the meaning is the same except for S477). Also, in the table above, "N501Y of RBD with N501Y variation" refers to the 501st tyrosine residue in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2, which has a variation in which the 501st position of the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2 is a tyrosine residue.

[0093] As can be understood from the table above, the amino acid sequences of the first region where the receptor-binding domain (RBD) of SARS-CoV-2 binds and the second region where the receptor-binding domain (RBD) of SARS-CoV-2 binds are not limited to sequence numbers 1, 59, 61, 2 or 57 respectively, and can be appropriately changed according to the function of each amino acid residue.

[0094] For example, the aspartic acid residue at position 1 from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of the first region of SARS-CoV-2 does not specifically interact with the RBD. However, if this amino acid residue is removed, the binding ability decreases. Therefore, it can be replaced by a glutamic acid residue with a chemical structure similar to aspartic acid. Furthermore, the arginine residue at position 15 from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of the first region of SARS-CoV-2 forms a salt bridge with the glutamic acid residue at position 19 of the sequence constituting the receptor-binding domain (RBD) of the first region of SARS-CoV-2, which helps stabilize the helical structure. However, the same stability can be achieved by replacing each residue with a lysine residue and an aspartic acid residue. The glycine residue at position 2 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) in the second region of SARS-CoV-2 is crucial for the receptor-binding domain (RBD) containing the N501Y variant, as exemplified by the UK variant SARS-CoV-2 (B.1.1.7). However, by replacing it with an alanine residue, a stronger binding affinity to the receptor-binding domain (RBD) in wild-type SARS-CoV-2 is obtained. Furthermore, the glutamine residue at position 3 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) in the second region of SARS-CoV-2 can be a glutamine residue. Furthermore, the leucine residue at position 6 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) in the second region of SARS-CoV-2 can be a methionine residue. Furthermore, the methionine residue at position 16 from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the second region can be replaced with a tryptophan residue. Moreover, by simultaneously replacing the glutamic acid residue at position 3, the leucine residue at position 6, and the methionine residue at position 16 from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 with glutamine, methionine, and tryptophan residues, a peptide that binds strongly to variant SARS-CoV-2 and exhibits antiviral activity can be prepared.

[0095] However, the sequence of the first region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably such that the first amino acid residue from the N-terminus is an aspartic acid residue. By setting the first amino acid residue from the N-terminus of the first region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2, the binding activity with the receptor-binding domain (RBD) of SARS-CoV-2 can be enhanced.

[0096] Furthermore, the sequence of the first region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably composed of an isoleucine residue at the 5th amino acid residue from the N-terminus. By setting the 5th position from the N-terminus of the sequence of the first region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 as an isoleucine residue, a stable interaction can be formed between the isoleucine residue at the 9th position from the N-terminus of the sequence constituting the first region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 and the phenylalanine residue at the 15th position from the N-terminus of the sequence constituting the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2. Furthermore, the sequence of the first region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably composed of an isoleucine residue at the 9th amino acid residue from the N-terminus. By setting the 9th position from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 as an isoleucine residue, it can be combined with the isoleucine residue at the 5th position from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, the valine residue at the 8th position from the N-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, and ...5th position from the N-terminus of the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, and the valine residue at the 8th position from the N-terminus of the sequence in the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, to form the second region. A stable interaction is formed between the leucine residue at position 11 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) of the first region with SARS-CoV-2, the isoleucine residue at position 12 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) of the second region with SARS-CoV-2, and the phenylalanine residue at position 15 from the N-terminus of the sequence constituting the binding site of the receptor-binding domain (RBD) of the second region with SARS-CoV-2. Furthermore, the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 preferably has tyrosine residue at position 10 from the N-terminus and methionine residue at position 13. High binding activity to the receptor-binding domain (RBD) of SARS-CoV-2 is achieved by setting the 10th position from the N-terminus of the sequence in the first region to a tyrosine residue and the 13th position to a methionine residue. Even if one of these two residues is replaced with an amino acid residue other than the tyrosine residue, the binding activity to the receptor-binding domain (RBD) of SARS-CoV-2 will be significantly reduced. Furthermore, the sequence in the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 preferably has an isoleucine residue at the 12th position from the N-terminus.By setting the 12th amino acid residue from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the first region, a stable interaction can be formed between the leucine residue at the 16th amino acid residue from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the first region and the valine residue at the 8th amino acid residue from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the second region. Preferably, the amino acid residue at the 16th amino acid residue from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the first region is a leucine residue. By setting the 16th position from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the first region as a leucine residue, a stable interaction can be formed between the isoleucine residue at the 12th position from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the first region, the alanine residue at the 4th position from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the second region, and the valine residue at the 8th position from the N-terminus of the sequence constituting the receptor-binding domain (RBD) of SARS-CoV-2 in the second region.

[0097] Regarding the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2, it is preferable that the first position from the N-terminus is a histidine residue. By setting the first position from the N-terminus of the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2 as a histidine residue, it is helpful to stabilize the helical bundle structure, and a salt bridge is formed with the glutamic acid residue at position 19 of the sequence of the first region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2, thereby stabilizing the turn structure.

[0098] Regarding the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, it is preferable that the 10th amino acid residue from the N-terminus is an aspartic acid residue. By setting the 10th position from the N-terminus of the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 to an aspartic acid residue, a salt bridge can be formed with the arginine residue at position 403 and the lysine residue at position 417 in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2. When the 10th position from the N-terminus of the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 is set as a glutamic acid residue, the glutamic acid residue cannot form a salt bridge with the arginine residue at position 403 and the lysine residue at position 417 in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2, which may reduce the binding activity with the receptor-binding domain (RBD) of SARS-CoV-2.

[0099] Furthermore, in the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2, the amino acid residue at position 13 from the N-terminus is preferably a tyrosine residue. By setting the 13th position from the N-terminus of the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2 to a tyrosine residue, a hydrogen bond can be formed with the aspartic acid residue at position 420 in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2.

[0100] Furthermore, the sequence of the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably such that the fourth amino acid residue from the N-terminus is an alanine residue. By setting the fourth amino acid residue from the N-terminus of the sequence of the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2, a stable interaction can be formed between the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 and the leucine residue from the N-terminus of the sequence constituting the first region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2. Furthermore, the sequence of the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably such that the eighth amino acid residue from the N-terminus is a valine residue. By setting the 8th position from the N-terminus of the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 as a valine residue, a stable interaction can be formed between the isoleucine residue at the 9th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, the isoleucine residue at the 12th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, the methionine residue at the 13th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, and the leucine residue at the 16th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2. Furthermore, the sequence of the second region's binding site to the receptor-binding domain (RBD) of SARS-CoV-2 is preferably composed of leucine residues at position 11 from the N-terminus. By setting leucine residues at position 11 from the N-terminus of the second region's binding site to the SARS-CoV-2 RBD, a stable interaction can be formed between the isoleucine residue at position 9 from the N-terminus of the first region's binding site to the SARS-CoV-2 RBD and the valine residue at position 8 from the N-terminus of the second region's binding site to the SARS-CoV-2 RBD. Furthermore, the sequence of the second region's binding site to the SARS-CoV-2 RBD is preferably composed of phenylalanine residues at position 15 from the N-terminus.By setting the 15th position from the N-terminus of the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 as a phenylalanine residue, a stable interaction can be formed between the isoleucine residue at the 5th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, the leucine residue at the 6th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2, and the isoleucine residue at the 9th position from the N-terminus of the sequence of the first region that binds to the receptor-binding domain (RBD) of SARS-CoV-2.

[0101] In addition to the above, the amino acid residue at position 14 from the N-terminus in the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can be any amino acid residue, but it is preferred to set it as a glutamic acid residue. By setting the 14th position from the N-terminus in the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 as a glutamic acid residue, the high hydrophilicity of the peptide can be maintained.

[0102] Furthermore, it is preferable that the 17th amino acid residue from the N-terminus in the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2 is a lysine residue. By setting the 17th position from the N-terminus in the sequence of the second region where it binds to the receptor-binding domain (RBD) of SARS-CoV-2 as a lysine residue, a salt bridge can be formed with the aspartic acid residue at position 420 in the amino acid sequence of the receptor-binding domain (RBD) of SARS-CoV-2, and hydrogen bonds can be formed with the tyrosine residue at position 421 and the aspartic acid residue at position 460.

[0103] Furthermore, the amino acid residue at position 18 from the N-terminus in the sequence of the second region that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can be any amino acid residue, but it is preferred to be an arginine residue. By setting the 18th position from the N-terminus of the second helix to an arginine residue, the hydrophilicity of the peptide can be maintained, and hydrogen bonds can be formed with the lysine residue at position 2 from the N-terminus of the first helix, which helps to stabilize the helical bundle structure.

[0104] Furthermore, even when the arginine residue at position 18 is replaced with a lysine residue, the peptide's hydrophilicity remains high.

[0105] Furthermore, a characteristic of the peptide of the present invention is that the 15th position of the amino acid sequence numbered 1, 59, or 61 is an arginine residue and the 19th position is a glutamic acid residue. By forming a salt bridge between the arginine residue at position 15 and the glutamic acid residue at position 19 in the amino acid sequence numbered 1, 59, or 61, the structure of the first helix can be stabilized. This, in turn, increases the binding rate of the peptide of the present invention to the receptor-binding domain (RBD) of SARS-CoV-2.

[0106] In the peptide of the present invention, the amino acid sequence may also be formed by replacing the arginine residue at position 15 and the glutamic acid residue at position 19 in the amino acid sequences numbered 1, 59, or 61 with lysine residue and aspartic acid residue, respectively. In other words, in the peptide of the present invention, the amino acid residue at position 15 and the amino acid residue at position 19 in the amino acid sequences numbered 1, 59, or 61 may be any combination of lysine residue and aspartic acid residue, or a combination of arginine residue and glutamic acid residue, with the combination of arginine residue and glutamic acid residue being particularly desirable. Even when the 15th position in sequence numbered 1, 59, or 61 is set as a lysine residue and the 19th position is set as an aspartic acid residue, a salt bridge can be formed between the lysine residue and the aspartic acid residue, which helps to stabilize the structure of the first helix. In particular, when the 15th position of sequence number 1, 59, or 61 is set as an arginine residue and the 19th position is set as a glutamic acid residue, the binding rate of the peptide of the present invention to the receptor-binding domain (RBD) of SARS-CoV-2 can be further improved compared to the case where the 15th position of sequence number 1 is set as a lysine residue and the 19th position is set as an aspartic acid residue.

[0107] Furthermore, one characteristic of the peptide of the present invention is that the second position in the amino acid sequence of sequence number 2 or 57 is a glycine residue. Because the second position in the amino acid sequence of sequence number 2 or 57 is a glycine residue, the peptide of the present invention exhibits excellent binding activity to the receptor-binding domain (RBD) for both wild-type SARS-CoV-2 and mutant SARS-CoV-2.

[0108] Here, wild-type SARS-CoV-2 refers to SARS-CoV-2 with the following amino acid sequence constituting the receptor-binding domain (RBD): position 339 is glycine, position 371 is serine, position 373 is serine, position 375 is serine, position 376 is threonine, position 405 is aspartic acid, position 408 is arginine, and position 9 is 100%. Position 417 is a lysine residue, position 440 is an aspartic acid residue, position 446 is a glycine residue, position 452 is a leucine residue, position 477 is a serine residue, position 478 is a threonine residue, position 484 is a glutamic acid residue, position 493 is a glutamine residue, position 496 is a glycine residue, position 498 is a glutamine residue, position 501 is an aspartic acid residue, and position 505 is a tyrosine residue. On the other hand, variant SARS-CoV-2 refers to SARS-CoV-2 with at least one variant selected from the group consisting of the following variants: a variant in the amino acid sequence constituting the receptor-binding domain (RBD) where position 339 is an aspartic acid residue, position 371 is a leucine or phenylalanine residue, position 373 is a proline residue, position 375 is a phenylalanine residue, position 376 is an alanine residue, position 405 is an aspartic acid residue, position 408 is a serine residue, and position 417 is an aspartic acid residue. Variations of asparagine residue or threonine residue, variation of position 440 becoming lysine residue, variation of position 446 becoming serine residue, variation of position 452 becoming arginine residue, variation of position 477 becoming asparagine residue, variation of position 478 becoming lysine residue, variation of position 484 becoming lysine residue, variation of glutamine residue or alanine residue, variation of position 493 becoming arginine residue, variation of position 496 becoming serine residue, variation of position 498 becoming arginine residue, variation of position 501 becoming tyrosine residue, and variation of position 505 becoming histidine residue. More specifically, as a variant of SARS-CoV-2, the following type of SARS-CoV-2 (PANGO system name: B.1.1.7, sometimes referred to as the British variant of SARS-CoV-2) can be cited: it has a variant in which position 501 of the amino acid sequence constituting the receptor binding domain (RBD) is a tyrosine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 452, 477, 478, 484, 493, 496, 498 and 505 are wild-type.Furthermore, as a variant of SARS-CoV-2, the following type of SARS-CoV-2 (PANGO systematic name: B.1.351, sometimes referred to as the South African variant of SARS-CoV-2) can be cited: it has a variation in the amino acid sequence constituting the receptor-binding domain (RBD) where position 417 is an aspartic acid residue, position 484 is a lysine residue, and position 501 is a tyrosine residue, and the amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 440, 446, 452, 477, 478, 493, 496, 498, and 505 are wild-type. Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 (PANGO system name: P.1, sometimes referred to as the Brazilian variant of SARS-CoV-2) can be cited: those with a variation in the amino acid sequence constituting the receptor-binding domain (RBD) where position 417 is a threonine residue, position 484 is a lysine residue, and position 501 is a tyrosine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 440, 446, 452, 477, 478, 493, 496, 498, and 505 are wild-type. Furthermore, as a variant of SARS-CoV-2, the following type of SARS-CoV-2 (PANGO systematic name: B.1.617.2, sometimes referred to as the Indian variant (δ-type) SARS-CoV-2) can be cited: it has a variation in which position 452 of the amino acid sequence constituting the receptor binding domain (RBD) is an arginine residue and position 478 is a lysine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 477, 484, 493, 496, 498, 501, and 505 are wild-type.Furthermore, as a variant of SARS-CoV-2, the following type of SARS-CoV-2 (PANGO systematic name: B.1.617.1, sometimes referred to as Indian variant (κ type) SARS-CoV-2) can be cited: it has a variant in which position 452 of the amino acid sequence constituting the receptor binding domain (RBD) is an arginine residue and position 484 is a glutamine residue, and amino acid residues at positions 339, 371, 373, 375, 376, 405, 408, 417, 440, 446, 477, 478, 493, 496, 498, 501, and 505 are wild-type. Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 (PANGO system name: B.1.1.529 / BA.1, sometimes referred to as the Omeprone variant (BA.1 system) SARS-CoV-2) can be cited: those with the following variations in the amino acid sequence constituting the receptor-binding domain (RBD): a 339th position as an aspartic acid residue, a 371st position as a leucine residue, a 373rd position as a proline residue, a 375th position as a phenylalanine residue, and a 417th position as an aspartic acid residue. The variants include: a lysine residue at position 440, a serine residue at position 446, an aspartic acid residue at position 477, a lysine residue at position 478, an alanine residue at position 484, an arginine residue at position 493, a serine residue at position 496, an arginine residue at position 498, a tyrosine residue at position 501, and a histidine residue at position 505, with the amino acid residues at positions 376, 405, 408, and 452 being wild-type.Furthermore, as a variant of SARS-CoV-2, the following types of SARS-CoV-2 (PANGO system name: B.1.1.529 / BA.2, sometimes referred to as the Omeprone variant (BA.2 system) SARS-CoV-2) can be cited: those with the following variations in the amino acid sequence constituting the receptor-binding domain (RBD): position 339 being an aspartic acid residue, position 371 being a phenylalanine residue, position 373 being a proline residue, position 375 being a phenylalanine residue, position 376 being an alanine residue, and position 40... The amino acid residues at positions 5, 408, 417, 440, 477, 484, 493, 498, 501, and 505 are all wild-type amino acid residues.

[0109] Furthermore, the sequence of the second region of the peptide of the present invention that binds to the receptor-binding domain (RBD) of SARS-CoV-2 can also be an amino acid sequence in which the glycine residue at position 2 in sequence number 2 or 57 is replaced by an alanine residue. When the amino acid residue at position 2 in sequence number 2 or 57 is set to an alanine residue, it exhibits excellent binding activity to the receptor-binding domain (RBD) of SARS-CoV-2 of the following types: those SARS-CoV-2 in which the amino acid residue at position 501 of wild-type SARS-CoV-2 and mutant SARS-CoV-2 is wild-type.

[0110] Furthermore, a characteristic of the peptide of the present invention is that the 18th position of the amino acid sequence of sequence number 2 or 57 is an arginine residue. Because the peptide of the present invention has an arginine residue at the 18th position of the amino acid sequence of sequence number 2 or 57, it exhibits excellent binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 and the receptor-binding domains (RBDs) of all the aforementioned variant SARS-CoV-2.

[0111] Here, the composition of the peptides of the present invention is illustrated in Table 6 below. The technical scope of the present invention is not limited to peptides containing the following specific amino acid sequences.

[0112] [Table 6]

[0113] For example, in the peptide of the present invention, the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 includes the following amino acid sequences (h), (i), (j), (k) or (l): (h) amino acid sequence number 56, (i) amino acid sequence number 59, (j) amino acid sequence number 61, (k) amino acid sequence number 63, or (l) amino acid sequence number 65, and the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 includes the amino acid sequence number 57.

[0114] Furthermore, in the peptide of the present invention, the sequence of the first region binding to the receptor-binding domain (RBD) of SARS-CoV-2 includes the following (m), (n), (o) or (p) amino acid sequences: (m) amino acid sequence number 4, (n) amino acid sequence number 6, (o) amino acid sequence number 7, or (p) amino acid sequence number 8, and the sequence of the second region binding to the receptor-binding domain (RBD) of SARS-CoV-2 includes amino acid sequences numbered 2, 3, 5 or 9.

[0115] These specific peptides are different from the LCB1 peptide (sequence number 10: DKEWILQKIYEIMRLLDELGHAEASMRVSDLIYEFMKKGDERLLEEAERLLEEVER (with 3 helices)) disclosed in L Cao et al., Science 370, 426-431 (2020), which contains 2 helices.

[0116] Contains peptides in which the full-length amino acid sequence of such specific peptides includes one amino acid sequence selected from the group consisting of sequence numbers 52-55, 58, 60, 62, 64 and 66 below. Serial Number 52: DKEWILQKIYEIMRKLDEDGHAEASMRVSDLIYEFMKKD Serial Number 53: DKEWILQKIYEIMRRLDEEGHAEASMRVSDLIYEFMKKD Serial Number 54: DKEWILQKIYEIMRRLDEEGHGEASLRVSDLIYEFMKKD Serial Number 55: DKEWILQKIYEIMRRLDEEGHGEASLRVSDLIYEFMKRD Serial Number 58: DKEWILQKIYEIMQRLDEEGHGEASLMVSDLIYEFMKRD Serial Number 60: DKLWILQKIYEIMVRLDEEGHGEASLMVSDLIYEFMKRD Serial Number 62: DKEWILYKIYEIMVRLDEEGHGEASLMVSDLIYEFMKRD Serial Number 64: DKLWILQKIYEIMQRLDEEGHGEASLMVSDLIYEFMKRD Serial number 66: DKEWILYKIYEIMQRLDEEGHGEASLMVSDLIYEFMKRD

[0117] Furthermore, regarding these specific peptides, as shown in the examples below, they exhibit excellent binding activity to the receptor-binding domain (RBD) of SARS-CoV-2. Here, binding activity can be determined by combining binding rate and degree of dissociation. For a specific peptide, there is no particular limitation on the system used to evaluate the binding activity to the receptor-binding domain (RBD) of SARS-CoV-2; a system utilizing surface plasma resonance (SPR) can be used. For example, the receptor-binding domain (RBD) of SARS-CoV-2 is fixed to the surface of a sensor chip, and a sample containing various analytes (peptides) is brought into contact with this surface. The binding rate is measured based on the change in the SPR angle caused by the binding of the receptor-binding domain (RBD) of SARS-CoV-2 to the peptide. Furthermore, on the surface of the sensor chip, a buffer solution without analyte was flowed through it while the receptor-binding domain (RBD) of SARS-CoV-2 was bound to the peptide. The degree of dissociation was measured based on the change in the SPR angle caused by the dissociation of the receptor-binding domain (RBD) of SARS-CoV-2 to the peptide.

[0118] Furthermore, the determination of the binding rate and dissociation degree of peptides to the receptor-binding domain (RBD) of SARS-CoV-2 is not limited to the surface plasma resonance (SPR) system, but can also be performed by systems that analyze the interactions of molecules in organisms, such as biofilm layer intervention (BLI).

[0119] Furthermore, the peptide of the present invention, provided it exhibits excellent binding activity to the receptor-binding domain (RBD) of SARS-CoV-2, may be a peptide with at least one amino acid bound to one of its N-terminus and C-terminus, and may also be in the following forms: a fusion peptide formed by fusing with other peptides or proteins; a peptide with an inserted non-natural amino acid; a peptide with attached tags or markers; and a peptide subjected to modifications other than those described above. For example, a fusion peptide may be fused with a membrane permeability peptide (CPP) so that it can be introduced into cells upon administration, but is not limited to this. The peptides of the present invention may also include peptides with one or more amino acids attached to at least one of the N-terminus and C-terminus of the peptides of the present invention, as well as fused peptides formed by fusing with other peptides or proteins, peptides with inserted non-natural amino acids, peptides with attached tags or markers, and peptides with modifications other than those described above.

[0120] <Method for Manufacturing Peptides> Since the peptides of the present invention are approximately 39 amino acid residues in length, they can be easily manufactured using conventional chemical synthesis methods. Examples of peptide synthesis methods include solid-phase synthesis and liquid-phase synthesis. Examples of solid-phase synthesis include methods using Boc (tert-butoxycarbonyl) or Fmoc (9-pyromethoxycarbonyl) as protecting groups for the amino groups. Furthermore, the aforementioned peptides can be synthesized using commercially available peptide synthesis apparatus employing solid-phase synthesis.

[0121] Furthermore, DNA encoding the aforementioned peptide can also be synthesized, and the peptide can be expressed in a host cell in which the DNA has been introduced. Host cells can be bacteria such as yeast and Escherichia coli, insect cells, animal cells, or plant cells. Alternatively, a cell-free protein synthesis system can be used to synthesize the peptide in vitro. However, the peptide of the present invention is preferably manufactured by chemical synthesis. For example, since the peptide of the present invention is approximately 39 amino acid residues in length, it is simpler to chemically synthesize it using conventional methods; and manufacturing under GMP (Good Manufacturing Practice: the "correct manufacturing specifications" required by manufacturers and distributors) standards is relatively easier than chemical synthesis.

[0122] <Pharmaceutical Compositions, Therapeutic Agents> The peptides of the present invention described above can be used as pharmaceutical compositions. As described above, the peptides of the present invention have significantly higher solubility in ultrapure water or buffer solutions and excellent binding activity to the receptor-binding domain (RBD) of SARS-CoV-2. Therefore, the peptides of the present invention can be used as pharmaceutical compositions for the treatment and / or prevention of novel coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2. In other words, the present invention pertains to the use of the above-mentioned peptides in the manufacture of pharmaceutical compositions for the treatment and / or prevention of novel coronavirus disease 2019 (COVID-19).

[0123] The target of administration of this pharmaceutical composition is not particularly limited, and may include mammals such as humans, monkeys, mice, rats, hamsters, rabbits, guinea pigs, cattle, pigs, dogs, horses, cats, goats, and sheep, preferably humans. The administration route of the pharmaceutical composition of the present invention can be either oral or non-oral. The dosage of the pharmaceutical composition of the present invention can be specified in various ways depending on the formulation method, administration method, administration time, age, weight, sex, pathological state, excretion rate, and reaction sensitivity of the target. The timing of administration of the pharmaceutical composition of the present invention is not particularly limited and can be arbitrary. It can be administered before, after, or during meals. Furthermore, the administration / ingestion period is not particularly limited.

[0124] The pharmaceutical composition of the present invention can be formulated using pharmaceutically permissible carriers and / or excipients by methods commonly practiced by those skilled in the art, thereby producing a unit dose form or being added to a multi-dose container. The pharmaceutical composition of the present invention can be formulated into a suitable dosage form depending on the method of administration. The pharmaceutical composition of the present invention can be manufactured, for example, according to known methods described in the Japanese Pharmacopoeia (JP), the United States Pharmacopeia (USP), or the European Pharmacopoeia (EP). Furthermore, it can also be used in conjunction with known or future novel coronavirus infection treatment and / or prevention medicines (including mRNA vaccines), or medicines for the treatment and / or prevention of other diseases. [Examples]

[0125] Hereinafter, the present invention will be described in further detail by way of embodiments, but the technical scope of the present invention is not limited to the following embodiments.

[0126] [Example 1] In this example, the LCB1 peptide (containing sequence number 10: DKEWILQKIYEIMRLLDELGHAEASMRVSDLIYEFMKKGDERLLEEAERLLEEVER DKEWILQKIYEIMRLLDELGHAEASMRVSDLIYEFMKKG (sequence number 11) (referred to as Ca1)) disclosed in L Cao et al., Science 370, 426-431 (2020) was used as a comparative example. Ca1 was modified to develop a peptide that exhibits excellent binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2. LCB1 is a peptide with 3 helices, and Ca1 is a peptide with 2 helices from the N-terminus of LCB1. The DKEWILQKIYEIMRLLDELG (serial number 4) of Ca1 is referred to as the first region, and the HAEASMRVSDLIYEFMKKG (serial number 12) is referred to as the second region. Modifications are applied to the first and second regions.

[0127] The amino acid sequences of the Ca1 peptide and the peptide designed in this embodiment are summarized in Table 7. Furthermore, in the amino acid sequences shown in Table 7, the amino acid residues derived from the amino acid sequence of the Ca1 peptide are enclosed in boxes.

[0128] [Table 7]

[0129] The results of CD spectroscopy measurements for all peptides shown in Table 7, performed according to the operating instructions (CD spectroscopy measurement operating instructions) detailed below, are shown in Figure 1. Figure 1 shows that Cb1, Cb2, Cb3, Cb4, Cb5, Cb6, and Cb7 are peptides in which the amino acid sequences in region 1 and region 2 do not form a helical structure. It also shows that Ca1, as expected based on the results for the LCB1 peptide disclosed in L Cao et al., Science 370, 426-431 (2020), has formed a helical structure.

[0130] In contrast, Ce1, which is defined as an aspartic acid residue at the C-terminus of the second region and can form a salt bridge with the second lysine residue from the N-terminus of the first region, is shown in Figure 1. The first helix contained in the first region and the second helix contained in the second region form a helical bundle structure, resulting in a more stable structure than Ca1. Therefore, Ce1 was tested for binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 according to the operating instructions (intermolecular interaction analysis operating instructions) described in detail below. The results are shown in Figure 2, which shows that it has the excellent characteristics of faster binding speed and lower dissociation.

[0131] [Example 2] In this example, a plaque reduction assay was performed on Ce1 designed in Example 1 according to the operating instructions (plaque reduction assay operating instructions) described in detail below to determine the reduction effect on the infectivity of wild-type SARS-CoV-2, and the IC50 value was calculated based on the results. Furthermore, for comparison, a plaque reduction assay was also performed on LCB1 peptide and Ca1 using wild-type SARS-CoV-2, and the IC50 values ​​were calculated.

[0132] The results of the plaque meiosis experiment performed on Ce1 are shown in Figure 3. The inhibition rate was calculated based on the number of plaques formed on each culture plate. The relationship between Ce1 peptide concentration and inhibition rate is shown in Figure 4. The result shows that the IC50 value of Ce1 was 1.5 nM.

[0133] Furthermore, the results of plaque reduction experiments performed on LCB1 peptide and Ca1 are shown in Figures 5 and 6, respectively, and the relationship between inhibition rate and peptide concentration is shown in Figures 7 and 8, respectively. These results show that the IC50 values ​​of LCB1 peptide and Ca1 are 5.7 nM and 106.7 nM, respectively.

[0134] Based on these results, it can be seen that Ce1 designed in Example 1 exhibits superior antiviral activity against wild-type SARS-CoV-2 compared to LCB1 peptide and Ca1.

[0135] [Example 3] In this example, Ce1 designed in Example 1 was further improved, and a peptide that exhibits better binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 was developed.

[0136] The amino acid sequences of the peptides designed in this embodiment are summarized in Table 8. Furthermore, in the amino acid sequences shown in Table 8, the amino acid residues derived from the amino acid sequence of the Ce1 peptide are enclosed in boxes.

[0137] [Table 8]

[0138] The binding activity of all peptides shown in Table 8 to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 was determined. The results showed that they could be divided into: peptides with higher binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 than Ce1 (Ce4, Ce9, Ce14, Ce15, and Ce16); peptides with the same binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 as Ce1 (Ce6, Ce8, Ce10, and Ce11); and peptides with lower binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2 than Ce1 (Ce2, Ce3, Ce5, Ce7, Ce12, Ce13, Ce17, and Ce18). As a representative example of peptides with higher receptor-binding domain (RBD) binding activity to wild-type SARS-CoV-2 than Ce1, the binding activity assay results for Ce4 are shown in Figures 9 and 10, and the binding activity assay results for Ce9 are shown in Figure 11. Furthermore, as a representative example of peptides with equivalent receptor-binding domain (RBD) binding activity to wild-type SARS-CoV-2 as Ce1, the binding activity assay results for Ce6 are shown in Figure 12. And as a representative example of peptides with lower receptor-binding domain (RBD) binding activity to wild-type SARS-CoV-2 than Ce1, the binding activity assay results for Ce5 are shown in Figure 13.

[0139] Furthermore, Ce4 and Ce9 establish the amino acid residues at positions 15 and 19 of the first helix as pairs of lysine and aspartic acid residues, and arginine and glutamic acid residues, respectively. This forms a salt bridge between the amino acid residues at positions 15 and 19 of the first helix, thereby stabilizing the structure of the first helix. The full-length amino acid sequences of Ce4 and Ce9 are shown in sequence numbers 52 and 53, respectively.

[0140] The results of measuring the binding activity of Ce4 against the receptor-binding domain (RBD) of wild-type SARS-CoV-2 are shown in Figures 9 and 10, and the results of measuring the binding activity of Ce9 against the receptor-binding domain (RBD) of wild-type SARS-CoV-2 are shown in Figure 11. Furthermore, Figures 9 and 10 show the results of measuring the binding activity of Ce4 against the receptor-binding domain (RBD) of wild-type SARS-CoV-2, but Figure 9 shows the results from the start of binding up to 720 seconds, and Figure 10 shows the results from the start of binding up to 3 hours and 2 minutes.

[0141] As shown in Figures 9 and 11, Ce4 and Ce9 significantly improved the binding rate compared to Ce1 (Figure 2). This result suggests that the formation of salt bridges within the first region stabilizes its structure, enhancing its binding activity to the receptor-binding domain (RBD) of wild-type SARS-CoV-2. In particular, Ce9, with arginine and glutamic acid residues at positions 15 and 19 respectively in the first region, exhibited even better binding activity than Ce4.

[0142] According to the results, Ce1 designed in Example 1 is preferably configured such that the amino acid residues at the 15th and 19th positions in the first region are respectively set as a pair of lysine residue and aspartic acid residue, and arginine residue and glutamic acid residue, and more preferably, in particular, as a pair of arginine residue and glutamic acid residue.

[0143] In particular, as shown in Figure 10, it can be understood that even after rinsing with buffer for 3 hours, Ce4 will not dissociate from the receptor-binding domain (RBD) of the temporarily bound wild-type SARS-CoV-2. This result also applies to Ce9. Therefore, it can be seen that the Ce4 and Ce9 prepared in this embodiment can maintain excellent binding activity with the receptor-binding domain (RBD) of wild-type SARS-CoV-2 for a long period of time.

[0144] Furthermore, the results of measuring the binding activity of Ce14, Ce15, and Ce16 prepared in this embodiment for the receptor-binding domain (RBD) of wild-type SARS-CoV-2 are shown in Figures 14, 15, and 16, respectively. As shown in Figures 14-16, Ce14, Ce15, and Ce16 exhibit higher binding activity compared to Ce1 (Figure 2).

[0145] [Example 4] In this example, a peptide exhibiting excellent binding activity against the receptor-binding domain (RBD) of mutant SARS-CoV-2 was developed. In Example 3, Ce9, which exhibited the best binding activity against the receptor-binding domain (RBD) of wild-type SARS-CoV-2, showed very excellent antiviral activity (not illustrated) with an IC50 value of 0.4 nM, based on the results of plaque meiosis assays using wild-type SARS-CoV-2.

[0146] However, for Ce9, plaque meiosis assays were performed using mutant SARS-CoV-2. The results showed an IC50 value of 13 nM against the UK mutant SARS-CoV-2 (B.1.1.7) and 1195 nM against the Brazilian mutant SARS-CoV-2 (P.1). That is, Ce9 exhibits exceptionally high antiviral activity specifically against wild-type SARS-CoV-2. In this embodiment, Ce9 was modified to develop a peptide that also exhibits excellent antiviral activity against mutant SARS-CoV-2. The amino acid sequences of the peptide designed in this embodiment are shown in Table 9. Furthermore, in the amino acid sequences shown in Table 9, amino acid residues derived from the modified Ce9 peptide amino acid sequence are enclosed in boxes.

[0147] [Table 9]

[0148] Studies on all peptides shown in Table 9 indicate that the Ce41 lineage contains peptides with high binding activity to the receptor-binding domains (RBDs) of wild-type SARS-CoV-2, UK variant SARS-CoV-2 (B.1.1.7), Brazilian variant SARS-CoV-2 (P.1), South African variant SARS-CoV-2 (B.1.351), Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and Indian variant (κ-type) SARS-CoV-2 (B.1.617.1). The results of determining the binding activity of Ce41 for the receptor-binding domain (RBD) of wild-type SARS-CoV-2, UK variant SARS-CoV-2 (B.1.1.7), Brazilian variant SARS-CoV-2 (P.1), South African variant SARS-CoV-2 (B.1.351), Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and Indian variant (κ-type) SARS-CoV-2 (B.1.617.1) are shown in Figures 17, 18, 19, 20, 21, and 22, respectively. Furthermore, the full-length amino acid sequence of Ce41 is shown at sequence number 54.

[0149] [Example 5] In this example, plaque reduction experiment was carried out using the British variant SARS-CoV-2 (B.1.1.7) for Ce41 designed in Example 4, thereby determining the effect of reducing viral infectivity and calculating the IC50 value based on the results.

[0150] The results of the plaque shaving experiment conducted on Ce41 using the UK variant SARS-CoV-2 (B.1.1.7) are shown in Figure 23. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 24. The results show that the IC50 value for Ce41 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.68 nM.

[0151] Based on the above results, it can be seen that Ce41 designed in Example 4 has excellent antiviral activity against the British variant SARS-CoV-2 (B.1.1.7).

[0152] [Example 6] In this example, the binding activity of Ce41 designed in Example 4 to the receptor binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) was measured, and the binding status of Ce41 to the receptor binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) was studied.

[0153] For Ce41, the binding activity against the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7) was measured for 3 hours and 2 minutes from the start of binding, and the results are shown in Figure 25.

[0154] Based on this result, it can be seen that even after rinsing with buffer for 3 hours, Ce41 does not dissociate from the temporarily bound receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7), and can sustainably maintain excellent binding activity to the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) for a long period of time. In order to achieve very high antiviral activity against the British variant SARS-CoV-2 (B.1.1.7) shown in Example 5, the characteristic of Ce41 in sustaining excellent binding activity to the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) for a long period of time is considered extremely important. Furthermore, the LCB1 peptide cannot maintain binding activity to the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) for a short period of time.

[0155] [Example 7] In this example, a peptide exhibiting even better binding activity than Ce41 developed in the above examples was developed. In this example, as shown in Table 10, Ce59 was designed by setting the 18th amino acid residue (lysine residue) in the second region of Ce41 as an arginine residue (enclosed in a box in Table 10). Furthermore, the full-length amino acid sequence of Ce59 is shown in sequence number 55.

[0156] [Table 10]

[0157] Regarding Ce59, the results of determining the binding activity of Ce59 with the receptor-binding domains (RBDs) of wild-type SARS-CoV-2, the UK variant SARS-CoV-2 (B.1.1.7), the Brazilian variant SARS-CoV-2 (P.1), the South African variant SARS-CoV-2 (B.1.351), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and the Indian variant (κ-type) SARS-CoV-2 (B.1.617.1) are shown in Figures 26, 27, 28, 29, 30, and 31, respectively. Based on these experimental results, Ce59 is a peptide with excellent binding activity to the receptor-binding domains (RBDs) of both the tested wild-type SARS-CoV-2 and all variant SARS-CoV-2. Furthermore, it can be seen that, especially for the receptor-binding domain (RBD) of the Brazilian variant SARS-CoV-2 (P.1) and the South African variant SARS-CoV-2 (B.1.351), it exhibits superior binding activity compared to Ce41 (Figures 28 and 29).

[0158] Furthermore, plaque reduction assays were performed on Ce59 using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) and the British variant SARS-CoV-2 (B.1.1.7) to determine the reduction effect on viral infectivity, and the IC50 value was calculated based on the results. The results of the plaque reduction assay performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) are shown in Figure 32. The inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 33. The IC50 of Ce59 against the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) was calculated to be 16 nM. As described above, Ce59 also exhibits excellent antiviral activity against the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2).

[0159] Similarly, the results of the plaque shaving experiment performed using the British variant SARS-CoV-2 (B.1.1.7) are shown in Figure 34. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 35. As a result, the IC50 value for Ce59 against the British variant SARS-CoV-2 (B.1.1.7) was calculated to be 0.2 nM. As shown in Example 5, compared to the IC50 value of 0.68 nM for Ce41 against the British variant SARS-CoV-2 (B.1.1.7), the IC50 value for Ce59 against the British variant SARS-CoV-2 (B.1.1.7) showed a result of 0.2 nM, indicating that it has superior antiviral activity against the British variant SARS-CoV-2 (B.1.1.7) compared to Ce41.

[0160] Furthermore, for Ce59, the binding activity against the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7) was measured for 3 hours and 2 minutes from the start of binding, and the results are shown in Figure 36. According to these results, even after rinsing with buffer for 3 hours, Ce59 did not dissociate from the temporarily bound receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7), indicating that it can sustainably maintain excellent binding activity against the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7) for a long period.

[0161] [Example 8] Regarding Ce41 and Ce59 developed in the above examples, the binding activity of Ce41 and Ce59 to the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) was measured. The results showed that Ce41 and Ce59 could not maintain binding to the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). These experimental results are shown in Figures 77 and 78. Therefore, in this example, a peptide exhibiting further superior binding activity compared to Ce59 developed in the above examples was developed. Ce113 was designed by replacing the 14th amino acid residue (arginine residue) in region 1 and the 7th amino acid residue (arginine residue) in region 2 of Ce59 with glutamine and methionine residues, respectively. The amino acid sequence of Ce113 is shown in Table 11, with the amino acid residues derived from the Ce59 amino acid sequence enclosed in boxes. Furthermore, the full-length amino acid sequence of Ce113 is shown in sequence number 58.

[0162] [Table 11]

[0163] The binding activity of Ce113 to the receptor-binding domains (RBDs) of the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), the Omecron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1), and the Omecron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2) was determined, and the results are shown in Figures 37, 38, 39, and 40, respectively. Based on these experimental results, Ce113 is a peptide with excellent binding activity to the receptor-binding domains (RBDs) of all tested SARS-CoV-2 variants. It is also known that Ce113 exhibits significantly higher binding activity than Ce59, especially for the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2).

[0164] [Example 9] In this example, a peptide exhibiting even better binding activity than Ce59 developed in the above examples was developed. Ce172 was designed by replacing the amino acid residue at position 3 (glutamic acid residue), position 14 (arginine residue), and position 7 (arginine residue) in the first region of Ce59 with leucine residue, valine residue, and methionine residue, respectively. The amino acid sequence of Ce172 is shown in Table 12, with the amino acid residues derived from the Ce59 amino acid sequence enclosed in boxes. Furthermore, the full-length amino acid sequence of Ce172 is shown in sequence number 60.

[0165] [Table 12]

[0166] The binding activity of Ce172 to the receptor-binding domains (RBDs) of the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), the Omecron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1), and the Omecron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2) was determined, and the results are shown in Figures 41, 42, 43, and 44, respectively. Based on these experimental results, Ce172 is a peptide with excellent binding activity to the receptor-binding domains (RBDs) of all tested SARS-CoV-2 variants. It is also known that Ce172 exhibits significantly higher binding activity than Ce59, especially for the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2).

[0167] Furthermore, for Ce172, plaque reduction experiments were performed using the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and the Omekkaron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) to determine the reduction effect on viral infectivity, and the IC50 value was calculated based on the results. The results of the plaque reduction experiment performed using the British variant SARS-CoV-2 (B.1.1.7) are shown in Figure 45. The inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 46. The results showed that the IC50 value of Ce172 against the British variant SARS-CoV-2 (B.1.1.7) was 0.0022 nM. As shown in Example 5, the IC50 value for Ce41 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.68 nM, and as shown in Example 7, the IC50 value for Ce59 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.2 nM. In contrast, the IC50 value for Ce172 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.0022 nM. Therefore, it can be seen that the UK variant SARS-CoV-2 (B.1.1.7) has superior antiviral activity compared to Ce41 and Ce59.

[0168] Similarly, the results of the plaque meiosis assay performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) are shown in Figure 47. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 48. As a result, the IC50 value of Ce172 for the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) was calculated to be 0.53 nM. As shown in Example 7, Ce59 has an IC50 value of 16 nM against the Indian variant (δ type) SARS-CoV-2 (B.1.617.2), while Ce172 has an IC50 value of 0.53 nM against the Indian variant (δ type) SARS-CoV-2 (B.1.617.2). Therefore, it can be seen that Ce59 has a much better antiviral activity against the Indian variant (δ type) SARS-CoV-2 (B.1.617.2).

[0169] Similarly, the results of the plaque shaving experiment performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) are shown in Figure 49. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 50. As a result, the IC50 value of Ce172 against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) was calculated to be 0.038 nM. As described above, Ce172 also exhibits excellent antiviral activity against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1).

[0170] [Example 10] In this example, a peptide exhibiting superior binding activity compared to Ce59 developed in the above examples was developed. Ce173 was designed by replacing the 3rd amino acid residue (glutamic acid residue), the 14th amino acid residue (arginine residue) in the first region of Ce59, and the 7th amino acid residue (arginine residue) in the second region with leucine residue, glutamine residue, and methionine residue, respectively. The amino acid sequence of Ce173 is shown in Table 13, with the amino acid residues derived from the Ce59 amino acid sequence enclosed in boxes. Furthermore, the full-length amino acid sequence of Ce173 is shown in sequence number 64.

[0171] [Table 13]

[0172] The binding activity of Ce173 to the receptor-binding domains (RBDs) of the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), the Omecron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1), and the Omecron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2) was determined, and the results are shown in Figures 51, 52, 53, and 54, respectively. Based on these experimental results, Ce173 is a peptide with excellent binding activity to the receptor-binding domains (RBDs) of all tested SARS-CoV-2 variants. It is also known that Ce173 exhibits significantly higher binding activity than Ce59, especially for the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2).

[0173] Furthermore, regarding Ce173, plaque reduction experiments were conducted using the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and the Omekkaron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) to determine the reduction effect on viral infectivity, and the inhibition rate was calculated based on the results. The results of the plaque reduction experiment using the British variant SARS-CoV-2 (B.1.1.7) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 55. The results show that Ce173 has excellent antiviral activity against the British variant SARS-CoV-2 (B.1.1.7).

[0174] Similarly, the results of the plaque meiosis assay performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 56. The results show that Ce173 has excellent antiviral activity against the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2).

[0175] Similarly, the results of the plaque meiosis assay performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 57. The results show that Ce173 has excellent antiviral activity against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1).

[0176] [Example 11] In this example, a peptide exhibiting even better binding activity than Ce59 developed in the above examples was developed. Ce174 was designed by replacing the 7th amino acid residue (glutamine residue) in the first region, the 14th amino acid residue (arginine residue) in the first region, and the 7th amino acid residue (arginine residue) in the second region of Ce59 with tyrosine residue, glutamine residue, and methionine residue, respectively. The amino acid sequence of Ce174 is shown in Table 14, with the amino acid residues derived from the Ce59 amino acid sequence enclosed in boxes. Furthermore, the full-length amino acid sequence of Ce174 is shown in sequence number 66.

[0177] [Table 14]

[0178] The results of determining the binding activity of Ce174 to the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), the Omecron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1), and the Omecron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2) are shown in Figures 58, 59, 60, and 61, respectively. These experimental results indicate that Ce174 is a peptide with excellent binding activity to the receptor-binding domain (RBD) of all tested SARS-CoV-2 variants. It is also known that Ce174 exhibits significantly higher binding activity than Ce59, especially for the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2).

[0179] Furthermore, plaque reduction experiments were conducted on Ce174 using the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and the Omekkaron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) to determine the reduction effect on viral infectivity, and the inhibition rate was calculated based on the results. The results of the plaque reduction experiment using the British variant SARS-CoV-2 (B.1.1.7) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 62. The results show that Ce174 has excellent antiviral activity against the British variant SARS-CoV-2 (B.1.1.7).

[0180] Similarly, the results of the plaque meiosis assay performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 63. The results show that Ce174 has excellent antiviral activity against the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2).

[0181] Similarly, the results of the plaque meiosis assay performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the inhibition rate calculated based on the number of plaques formed on each culture plate are shown in Figure 64. The results show that Ce174 has excellent antiviral activity against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1).

[0182] [Example 12] In this example, a peptide exhibiting even better binding activity than Ce59 developed in the above examples was developed. Ce149 was designed by replacing the 7th amino acid residue (glutamine residue) in the first region, the 14th amino acid residue (arginine residue) in the first region, and the 7th amino acid residue (arginine residue) in the second region of Ce59 with tyrosine residue, valine residue, and methionine residue, respectively. The amino acid sequence of Ce149 is shown in Table 15, with the amino acid residues derived from the Ce59 amino acid sequence enclosed in boxes. Furthermore, the full-length amino acid sequence of Ce149 is shown in sequence number 62.

[0183] [Table 15]

[0184] The results of determining the binding activity of Ce149 with the receptor-binding domains (RBDs) of the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), the Omecron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1), and the Omecron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2) are shown in Figures 65, 66, 67, and 68, respectively. These experimental results indicate that Ce149 is a peptide with excellent binding activity to the receptor-binding domains (RBDs) of all tested SARS-CoV-2 variants. It is also known that Ce149 exhibits significantly higher binding activity than Ce59, especially for the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) and the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2).

[0185] Furthermore, for Ce149, plaque reduction experiments were performed using the British variant SARS-CoV-2 (B.1.1.7), the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2), and the Omekkaron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) to determine the reduction effect on viral infectivity, and the IC50 value was calculated based on the results. The results of the plaque reduction experiment performed using the British variant SARS-CoV-2 (B.1.1.7) are shown in Figure 69. The inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 70. As a result, the IC50 value for Ce149 against the British variant SARS-CoV-2 (B.1.1.7) was calculated to be 0.0021 nM. As shown in Example 5, the IC50 value for Ce41 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.68 nM, and as shown in Example 7, the IC50 value for Ce59 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.2 nM. In contrast, the IC50 value for Ce149 against the UK variant SARS-CoV-2 (B.1.1.7) is 0.0021 nM. Therefore, it can be seen that the UK variant SARS-CoV-2 (B.1.1.7) has superior antiviral activity compared to Ce41 and Ce59.

[0186] Similarly, the results of the plaque meiosis assay performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) are shown in Figure 71. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 72. As a result, the IC50 value for Ce149 against the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) was calculated to be 0.15 nM. As shown in Example 7, the IC50 value for Ce59 against the Indian variant (δ type) SARS-CoV-2 (B.1.617.2) was 16 nM, while the IC50 value for Ce149 against the Indian variant (δ type) SARS-CoV-2 (B.1.617.2) was 0.15 nM. Therefore, it can be seen that the Indian variant (δ type) SARS-CoV-2 (B.1.617.2) has a much better antiviral activity than Ce59.

[0187] Similarly, the results of the plaque shaving experiment performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) are shown in Figure 73. Furthermore, the inhibition rate was calculated based on the number of plaques formed on each culture plate, and the relationship between peptide concentration and inhibition rate is shown in Figure 74. As a result, the IC50 value of Ce149 against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) was calculated to be 1 nM. As described above, Ce149 also exhibits excellent antiviral activity against the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1).

[0188] [Example 13] In this example, the CD spectra of Ce4, Ce9, Ce41, Ce59, Ce113, Ce149, Ce172, Ce173 and Ce174 developed in the above examples were measured, and the results are shown in Figure 75. As shown in Figure 75, Ce4, Ce9, Ce41, Ce59, Ce113, Ce149, Ce172, Ce173 and Ce174 all form a helical bundle structure with the first helix contained in the first region and the second helix contained in the second region, indicating that a stable structure has been obtained.

[0189] [Example 14] In this example, the three-dimensional structure of the complex of Ce41 and the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7) developed in the above examples was analyzed. A purified protein solution of the Ce41 and receptor-binding domain (RBD) complex of the British variant SARS-CoV-2 (B.1.1.7) was concentrated using an Amicon ultra-concentrator manufactured by Merck Millipore. The obtained purified protein solution was placed in a mosquito LCP manufactured by SPT Labtech, and crystal droplets were prepared using a crystallization plate manufactured by Violamo. The obtained three-dimensional crystals were subjected to cryogenic treatment using liquid nitrogen. X-ray diffraction experiments were performed using the automated beamline measurement system of the large-scale radioluminescence facility SPring-8 (Sayao District, Hyogo Prefecture, Japan), using X-rays with a wavelength of 1 Å, and diffraction data were collected. The data was processed using the KAMO automated data processing system to obtain a dataset, and the initial phase was determined using a phase meter for this dataset. The atomic model was constructed using COOT and refined using Refmac5 and PHENIX to determine the three-dimensional structure of Ce41 and the receptor-binding domain (RBD) in the UK variant SARS-CoV-2 (B.1.1.7). The Ce41 structural model was represented using PyMOL, and the interaction between the lysine residue at position 2 in region 1 and the five C-terminal residues in region 2 was analyzed. The results are shown in Figure 76. The analysis revealed that the lysine residue at position 2 in region 1 forms hydrogen bonds with the phenylalanine residue at position 15 (the 35th amino acid residue in terms of Ce41 as a whole) and the lysine residue at position 18 (the 38th amino acid residue in terms of Ce41 as a whole) in region 2. Furthermore, it is known that the lysine residue at position 2 in region 1 and the aspartic acid residue at position 19 in region 2 (the amino acid residue at position 39 in terms of Ce41 as a whole) form a salt bridge, thus indicating that these interactions contribute to the stabilization of the helical bundle structure of Ce41.

[0190] [Example 15] In this example, Ce4, Ce9, Ce41 and Ce59 developed in the above examples are dissolved in ultrapure water, and their solubility in ultrapure water is calculated.

[0191] Ce4, Ce9, Ce41, and Ce59, having the above-mentioned amino acid sequences, were chemically synthesized and dissolved in ultrapure water. Specifically, the chemically synthesized peptide was added to 250 μL of ultrapure water, and the solution was pipetted a sufficient number of times using a micropipette, and allowed to stand at room temperature. If no dissolution residue was observed, the peptide was added again, and the same operation was repeated. If dissolution residue was observed, the solution was allowed to stand for 10 minutes, and the solution was pipetted a sufficient number of times using a micropipette, and allowed to stand at room temperature. This step was repeated twice, and the concentration was determined using a NanoPhotometer NP80 micro-spectrophotometer manufactured by IMPLEN to evaluate the solubility in ultrapure water. The results are shown in Table 16.

[0192] [Table 16] Solubility (mM) Ce4 44 Ce9 5.2 Ce41 6.1 Ce59 6.1

[0193] According to these results, Ce4, Ce9, Ce41 and Ce59 achieved extremely high solubility in ultrapure water and exhibited extremely high binding activity to the receptor-binding domain (RBD) of SARS-CoV-2.

[0194] [Example 16] In this example, Ce113, Ce149, Ce172, Ce173 and Ce174 developed in the above examples were dissolved in 50 mM HEPES buffer solution (pH 8.0), and their solubility in 50 mM HEPES buffer solution (pH 8.0) was calculated.

[0195] Ce113, Ce149, Ce172, Ce173, and Ce174, having the above-mentioned amino acid sequences, were chemically synthesized and dissolved in 50 mM HEPES buffer solution (pH 8.0). Specifically, the chemically synthesized peptides were added to 250 μL of 50 mM HEPES buffer solution (pH 8.0), and the solution was pipetted a sufficient number of times using a micropipette, and allowed to stand at room temperature. If no dissolution residue remained, the peptides were added again, and the same operation was repeated. If dissolution residue appeared, the solution was allowed to stand for 10 minutes, and the solution was pipetted a sufficient number of times using a micropipette, and allowed to stand at room temperature. This step was repeated twice, and the concentration was determined using a NanoPhotometer NP80 micro-spectrophotometer manufactured by IMPLEN, and the solubility in 50 mM HEPES buffer solution (pH 8.0) was evaluated. The results are shown in Table 17.

[0196] [Table 17] Solubility (mM) Ce113 2.5 Ce149 1.3 Ce172 1.1 Ce173 1.5 Ce174 1.6

[0197] Based on these results, Ce113, Ce149, Ce172, Ce173 and Ce174 exhibited extremely high solubility in 50 mM HEPES buffer solution (pH 8.0) and extremely high binding activity to the receptor-binding domain (RBD) of SARS-CoV-2.

[0198] [Experimental Operation Instructions] <Instructions for Intermolecular Interaction Analysis> These instructions describe the binding rate and dissociation degree of a specific peptide designed and chemically synthesized in this embodiment with the receptor-binding domain (RBD) of SARS-CoV-2. In this embodiment, the Cytiva Biacore S200 and the Cytiva Biotin CAPture Kit, Series S (contents: Sensor Chip CAP, Biotin CAPture reagent, regeneration solution) were used to analyze the intermolecular interaction between the receptor-binding domain (RBD) of SARS-CoV-2 and the target peptide. When recording the measurement data, the Kinetics multi-cycle using Biotin CAP program of the Cytiva Biacore S200 control software was used.

[0199] First, the Sensor Chip CAP was inserted into the Biacore S200, and the operating buffer was flowed through at a flow rate of 65 mL / day for 12 hours. The operating buffer was a solution prepared by diluting Cytiva's HBS-EP+ buffer 10x by 10x with ultrapure water. Then, the regeneration solution was injected three times for 1 minute each. After that, the Biotin Capture reagent was flowed through at a flow rate of 2 μL / min for 300 seconds, the biotinylated RBD prepared at 1.0 μg / mL was flowed through at a flow rate of 10 μL / min for 80 seconds, the operating buffer was flowed through at a flow rate of 30 μL / min for 720 seconds (3 hours and 2 minutes for continuous long-term studies of binding status), and the regeneration solution was flowed through at a flow rate of 10 μL / min for 120 seconds. This series of four steps was repeated three times.

[0200] Subsequently, the Biotin Capture reagent was passed through at a flow rate of 2 μL / min for 300 seconds, the prepared biotinylated RBD (1.0 μg / mL) was passed through at a flow rate of 10 μL / min for 80 seconds, the target peptide was passed through at a flow rate of 30 μL / min for 120 seconds, the operating buffer was passed through at a flow rate of 30 μL / min for 600 seconds (3 hours for continuous long-term studies of binding status), and the regeneration solution was passed through at a flow rate of 10 μL / min for 120 seconds. This series of five steps was repeated depending on the number of target peptides to be measured to analyze the intermolecular interactions between the receptor-binding domain (RBD) of SARS-CoV-2 and each peptide.

[0201] The target peptide is prepared to any concentration by diluting it in an operating buffer to a final concentration of 0.1% (v / v) with dimethyl monoxide (dilution buffer). The 0 nM solution of the target peptide is prepared using the dilution buffer.

[0202] <CD Spectroscopy Measurement Instructions> In these instructions, the far-ultraviolet circularly polarized dichroism (CD) spectrum of the specific peptide designed and chemically synthesized in this embodiment is measured. Based on the CD spectrum measured according to these instructions, it is possible to evaluate whether the peptide has formed the target helical structure and helical bundle structure.

[0203] The target peptide powder was dissolved in TBS (20 mM hydroxymethylaminomethane hydrochloride, pH 8.0, 150 mM NaCl) to prepare a 20 μM solution. 200 μL of the peptide solution was then added to a 1 mm colorimetric tube. For CD spectroscopy measurements, a J-720 circular dichroism dispersant manufactured by Nippon Spectrophotometer Co., Ltd. was used. Recordings were taken at 25°C at 0.5 nm intervals within the wavelength range of 250 nm to 195 nm at a scan rate of 20 nm / min.

[0204] <Plexus Meiosis Experiment Instructions> These instructions describe the counting of SARS-CoV-2-infected cells. Based on the cell counts obtained according to these instructions, the inhibitory effect of the peptide prepared in this example on SARS-CoV-2 infection can be evaluated.

[0205] First, one day before the assay date, virus-sensitive cells VeroE6 / TMPRSS2 (Matsuyama et al., Proc Natl Acad Sci USA 117:7001-7003, 2020) were seeded into 24-well culture dishes at a rate of 1×10⁵ cells / well.

[0206] On the assay day, the SARS-CoV-2 NIID strain was diluted to 100 TCID50 / 180 μL using a serum- and antibiotic-free culture medium. Subsequently, a 10-fold dilution series of the peptide solution was prepared using TBS (20 mM hydroxymethylaminomethane hydrochloride, pH 8.0, 150 mM NaCl), and 20 μL of each solution was mixed with the virus solution (the control group was prepared using 20 μL of mixed TBS). As an example, final peptide concentrations of 2 μM, 400 nM, 80 nM, 16 nM, 3.2 nM, 640 pM, and 128 pM were prepared. The control group was prepared using 2% DMSO.

[0207] Next, the culture medium of VeroE6 / TMPRSS2 cells inoculated the previous day was extracted, and virus / peptide solution (200 μL) was added. The cells were then cultured at 37°C for 1 hour. Subsequently, the supernatant was extracted, and the cells were washed twice with PBS. 500 μL of methylcellulose viscous medium (E-MEM medium containing 1% methylcellulose and 2% bovine serum) was added. Then, the cells were cultured in a CO2 incubator for 2 days.

[0208] After culturing, firstly, the methylcellulose viscous medium was removed, and 3.7% formaldehyde was added to the cells for fixation for 2 hours. Then, the formaldehyde was removed, and the culture dishes were washed with tap water. Next, the live cells were stained with 1% crystal violet to count the number of plaques (clusters of dead cells caused by viral infection). Then, the number of plaques in the virus-infected area treated only with TBS and in the peptide-treated areas at various concentrations was calculated to determine the 50% inhibitory concentration (IC50 value). [Sequence listing non-key text]

[0209] Sequence Numbers 1-66 Synthetic Peptides All publications, patents and patent applications cited in this specification are incorporated herein by reference. [Simplified Explanation of the Diagram]

[0054] Figure 1 shows the CD spectrum characteristics of Ca1, Cb1, Cb2, Cb3, Cb4, Cb5, Cb6, Cb7 and Ce1 prepared in the examples. Figure 2 shows the characteristics of the results obtained by measuring the interaction between Ce1 prepared in the examples and the receptor-binding domain (RBD) in wild-type SARS-CoV-2. Figure 3 shows a photograph of the results of the plaque reduction experiment performed using wild-type SARS-CoV-2 with Ce1 prepared in the examples, and a graph showing the concentration conditions of Ce1. Figure 4 shows the characteristics of the relationship between Ce1 peptide concentration and inhibition rate shown in Figure 3. Figure 5 shows a photograph of the results of the plaque reduction experiment performed using wild-type SARS-CoV-2 with LCB1 peptide, and a graph showing the concentration conditions of LCB1. Figure 6 shows a photograph of the results of the plaque reduction experiment performed using wild-type SARS-CoV-2 with Ca1, and a graph showing the concentration conditions of Ca1. Figure 7 is a characteristic graph showing the relationship between LCB1 peptide concentration and inhibition rate as shown in Figure 5. Figure 8 is a characteristic graph showing the relationship between Ca1 peptide concentration and inhibition rate as shown in Figure 6. Figure 9 is a characteristic graph showing the results of measuring the interaction between Ce4 prepared in the example and the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 10 is a characteristic graph showing the results of measuring the interaction between Ce4 prepared in the example and the receptor-binding domain (RBD) of wild-type SARS-CoV-2 for 3 hours and 2 minutes from the start of binding. Figure 11 is a characteristic graph showing the results of measuring the interaction between Ce9 prepared in the example and the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 12 is a characteristic graph showing the results of measuring the interaction between Ce6 prepared in the example and the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 13 is a characteristic graph showing the interaction results of Ce5 prepared in the examples with the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 14 is a characteristic graph showing the interaction results of Ce14 prepared in the examples with the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 15 is a characteristic graph showing the interaction results of Ce15 prepared in the examples with the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 16 is a characteristic graph showing the interaction results of Ce16 prepared in the examples with the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 17 is a characteristic graph showing the interaction results of Ce41 prepared in the examples with the receptor-binding domain (RBD) of wild-type SARS-CoV-2.Figure 18 shows the characteristics of the Ce41 prepared in the examples, measured for its interaction with the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7). Figure 19 shows the characteristics of the Ce41 prepared in the examples, measured for its interaction with the receptor-binding domain (RBD) of the Brazilian variant SARS-CoV-2 (P.1). Figure 20 shows the characteristics of the Ce41 prepared in the examples, measured for its interaction with the receptor-binding domain (RBD) of the South African variant SARS-CoV-2 (B.1.351). Figure 21 shows the characteristics of the Ce41 prepared in the examples, measured for its interaction with the receptor-binding domain (RBD) of the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2). Figure 22 shows the characteristics of the interaction between Ce41 prepared in the examples and the receptor-binding domain (RBD) of Indian variant (κ type) SARS-CoV-2 (B.1.617.1). Figure 23 shows a photograph of the results of a plaque shavings assay performed using British variant SARS-CoV-2 (B.1.1.7) with Ce41 prepared in the examples, and a graph showing the concentration conditions of Ce41. Figure 24 shows the characteristics of the relationship between Ce41 peptide concentration and inhibition rate shown in Figure 23. Figure 25 shows the characteristics of the interaction between Ce41 prepared in the examples and the receptor-binding domain (RBD) of British variant SARS-CoV-2 (B.1.1.7) for 3 hours and 2 minutes from the start of binding. Figure 26 shows the characteristics of the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of wild-type SARS-CoV-2. Figure 27 is a characteristic graph showing the results of measuring the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7). Figure 28 is a characteristic graph showing the results of measuring the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of the Brazilian variant SARS-CoV-2 (P.1). Figure 29 is a characteristic graph showing the results of measuring the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of the South African variant SARS-CoV-2 (B.1.351). Figure 30 is a characteristic graph showing the results of measuring the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2).Figure 31 is a graph showing the characteristics of the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of Indian variant (κ type) SARS-CoV-2 (B.1.617.1). Figure 32 is a photograph showing the results of a plaque reduction experiment performed using Indian variant (δ type) SARS-CoV-2 (B.1.617.2) with Ce59 prepared in the examples, and a graph showing the concentration conditions of Ce59. Figure 33 is a graph showing the relationship between Ce59 peptide concentration and inhibition rate shown in Figure 32. Figure 34 is a photograph showing the results of a plaque reduction experiment performed using British variant SARS-CoV-2 (B.1.1.7) with Ce59 prepared in the examples, and a graph showing the concentration conditions of Ce59. Figure 35 is a graph showing the relationship between Ce59 peptide concentration and inhibition rate shown in Figure 34. Figure 36 shows the characteristics of Ce59 prepared in the examples, measured from the start of binding, interacting with the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7) for 3 hours and 2 minutes. Figure 37 shows the characteristics of Ce113 prepared in the examples, measured with the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7). Figure 38 shows the characteristics of Ce113 prepared in the examples, measured with the receptor-binding domain (RBD) of the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1). Figure 39 shows the characteristics of Ce113 prepared in the examples, measured with the receptor-binding domain (RBD) of the Omekkaron variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 40 shows the characteristics of the interaction between Ce113 prepared in the examples and the receptor-binding domain (RBD) of the Omekkaron variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2). Figure 41 shows the characteristics of the interaction between Ce172 prepared in the examples and the receptor-binding domain (RBD) of the UK variant SARS-CoV-2 (B.1.1.7). Figure 42 shows the characteristics of the interaction between Ce172 prepared in the examples and the receptor-binding domain (RBD) of the Indian variant (δ type) SARS-CoV-2 (B.1.617.1).Figure 43 is a graph showing the characteristics of the interaction between Ce172 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 44 is a graph showing the characteristics of the interaction between Ce172 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2). Figure 45 shows a photograph of the results of a plaque meiosis assay performed using the UK variant SARS-CoV-2 (B.1.1.7) with Ce172 prepared in the examples, and a graph showing the concentration conditions of Ce172. Figure 46 is a graph showing the relationship between Ce172 peptide concentration and inhibition rate shown in Figure 45. Figure 47 shows photographs of the results of a plaque reduction experiment performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1) with Ce172 prepared in the examples, and a graph showing the concentration conditions of Ce172. Figure 48 is a characteristic graph showing the relationship between Ce172 peptide concentration and inhibition rate shown in Figure 47. Figure 49 shows photographs of the results of a plaque reduction experiment performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) with Ce172 prepared in the examples, and a graph showing the concentration conditions of Ce172. Figure 50 is a characteristic graph showing the relationship between Ce172 peptide concentration and inhibition rate shown in Figure 49. Figure 51 is a characteristic graph showing the results of measuring the interaction between Ce173 prepared in the examples and the receptor-binding domain (RBD) in the British variant SARS-CoV-2 (B.1.1.7). Figure 52 is a characteristic graph showing the results of measuring the interaction between Ce173 prepared in the examples and the receptor-binding domain (RBD) of the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1). Figure 53 is a characteristic graph showing the results of measuring the interaction between Ce173 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 54 is a characteristic graph showing the results of measuring the interaction between Ce173 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2). Figure 55 shows the results of a plaque meiosis assay performed on Ce173 prepared in the examples using the British variant SARS-CoV-2 (B.1.1.7), and a graph showing the relationship between Ce173 peptide concentration and inhibition rate.Figure 56 shows photographs of the plaque reduction assay results performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1) with Ce173 prepared in the examples, and a graph showing the relationship between Ce173 peptide concentration and inhibition rate. Figure 57 shows photographs of the plaque reduction assay results performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) with Ce173 prepared in the examples, and a graph showing the relationship between Ce173 peptide concentration and inhibition rate. Figure 58 shows a characteristic graph of the results obtained by measuring the interaction between Ce174 prepared in the examples and the receptor-binding domain (RBD) in the British variant SARS-CoV-2 (B.1.1.7). Figure 59 is a characteristic graph showing the results of measuring the interaction between Ce174 prepared in the examples and the receptor-binding domain (RBD) of the Indian variant (δ type) SARS-CoV-2 (B.1.617.1). Figure 60 is a characteristic graph showing the results of measuring the interaction between Ce174 prepared in the examples and the receptor-binding domain (RBD) of the Omega-Jon variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 61 is a characteristic graph showing the results of measuring the interaction between Ce174 prepared in the examples and the receptor-binding domain (RBD) of the Omega-Jon variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2). Figure 62 shows photographs of the plaque reduction assay results performed using the British variant SARS-CoV-2 (B.1.1.7) with Ce174 prepared in the examples, and a graph showing the relationship between Ce174 peptide concentration and inhibition rate. Figure 63 shows photographs of the plaque reduction assay results performed using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1) with Ce174 prepared in the examples, and a graph showing the relationship between Ce174 peptide concentration and inhibition rate. Figure 64 shows photographs of the plaque reduction assay results performed using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) with Ce174 prepared in the examples, and a graph showing the relationship between Ce174 peptide concentration and inhibition rate. Figure 65 is a characteristic graph showing the results of measuring the interaction between Ce149 prepared in the examples and the receptor-binding domain (RBD) of the British variant SARS-CoV-2 (B.1.1.7). Figure 66 is a characteristic graph showing the results of measuring the interaction between Ce149 prepared in the examples and the receptor-binding domain (RBD) of the Indian variant (δ-type) SARS-CoV-2 (B.1.617.1).Figure 67 is a graph showing the characteristics of the interaction between Ce149 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 68 is a graph showing the characteristics of the interaction between Ce149 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.2 system) SARS-CoV-2 (B.1.1.529 / BA.2). Figure 69 shows a photograph of the results of a plaque retardation assay performed using the UK variant SARS-CoV-2 (B.1.1.7) with Ce149 prepared in the examples, and a graph showing the concentration conditions of Ce149. Figure 70 is a graph showing the relationship between Ce149 peptide concentration and inhibition rate as shown in Figure 69. Figure 71 shows photographs of the results of a plaque reduction experiment conducted using the Indian variant (δ-type) SARS-CoV-2 (B.1.617.2) with Ce149 prepared in the examples, and a graph showing the concentration conditions of Ce149. Figure 72 is a characteristic graph showing the relationship between Ce149 peptide concentration and inhibition rate shown in Figure 71. Figure 73 shows photographs of the results of a plaque reduction experiment conducted using the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1) with Ce149 prepared in the examples, and a graph showing the concentration conditions of Ce149. Figure 74 is a characteristic graph showing the relationship between Ce149 peptide concentration and inhibition rate shown in Figure 73. Figure 75 shows the CD spectrum characteristics of Ce4, Ce9, Ce41, Ce59, Ce113, Ce149, Ce172, Ce173, and Ce174 prepared in the examples. Figure 76 shows the characteristics of the interaction between the lysine residue at position 2 in the first region and the five C-terminal residues in the second region of the three-dimensional structural model of Ce41 prepared in the examples. Figure 77 shows the characteristics of the interaction between Ce41 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1). Figure 78 shows the characteristics of the interaction between Ce59 prepared in the examples and the receptor-binding domain (RBD) of the Omeprone variant (BA.1 system) SARS-CoV-2 (B.1.1.529 / BA.1).

Claims

1. A peptide comprising an amino acid sequence selected from the group consisting of sequence numbers 52 to 55.

2. A peptide having a first region and a second region in a direction from the N-terminus to the C-terminus, wherein the first region comprises an amino acid sequence selected from (h), (i), (j), (k) or (l), namely, (h) amino acid sequence number 56, (i) amino acid sequence number 59, (j) amino acid sequence number 61, (k) amino acid sequence number 63, or (l) amino acid sequence number 65, and the second region comprises an amino acid sequence number 57 and binds to the receptor-binding domain (RBD) of SARS-CoV-2.

3. A peptide comprising an amino acid sequence numbered 58 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

4. A peptide comprising an amino acid sequence numbered 60 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

5. A peptide comprising an amino acid sequence numbered 62 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

6. A peptide comprising an amino acid sequence of sequence number 64 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

7. A peptide comprising an amino acid sequence numbered 66 and binding to the receptor-binding domain (RBD) of SARS-CoV-2.

8. A pharmaceutical composition comprising a peptide as an active ingredient, as claimed in any one of claims 1 to 7.

9. The pharmaceutical composition of claim 8, used for the treatment of novel coronavirus infection.

10. The pharmaceutical composition for treating novel coronavirus infection as claimed in claim 9, wherein the novel coronavirus infection is caused by infection with any of the following SARS-CoV-2: wild-type SARS-CoV-2, wherein the amino acid residue at position 339 of the receptor-binding domain (RBD) is a glycine residue, the amino acid residue at position 371 is a serine residue, the amino acid residue at position 373 is a serine residue, the amino acid residue at position 375 is a serine residue, the amino acid residue at position 376 is a threonine residue, and the amino acid residue at position 405 is... The amino acid residues are aspartic acid residues, the amino acid residue at position 408 is arginine residue, the amino acid residue at position 417 is lysine residue, the amino acid residue at position 440 is aspartic acid residue, the amino acid residue at position 446 is glycine residue, the amino acid residue at position 452 is leucine residue, the amino acid residue at position 477 is serine residue, the amino acid residue at position 478 is threonine residue, the amino acid residue at position 484 is glutamic acid residue, the amino acid residue at position 493 is glutamine residue, and the amino acid residue at position 496 is glycine residue. The amino acid residues at positions 498, 501, and 505 are glutamine, tyrosine, and lysine, respectively. In variant 1 SARS-CoV-2, the amino acid residue at position 501 is tyrosine. In variant 2 SARS-CoV-2, the amino acid residue at position 484 is lysine. In variant 3 SARS-CoV-2, the amino acid residue at position 417 is aspartamine, the amino acid residue at position 484 is lysine, and the amino acid residue at position 505 is tyrosine. The amino acid residues are tyrosine residues; in variant 4 of SARS-CoV-2, the amino acid residue at position 417 is threonine residue, the amino acid residue at position 484 is lysine residue, and the amino acid residue at position 501 is tyrosine residue; in variant 5 of SARS-CoV-2, the amino acid residue at position 452 is arginine residue, and the amino acid residue at position 478 is lysine residue; in variant 6 of SARS-CoV-2, the amino acid residue at position 452 is arginine residue, and the amino acid residue at position 484 is glutamine residue.The 7th variant of SARS-CoV-2 has the following amino acid residues: aspartic acid at position 339, leucine at position 371, proline at position 373, phenylalanine at position 375, aspartic acid at position 417, lysine at position 440, serine at position 446, and so on. The amino acid residues at positions 476, 48, 493, 496, 498, 501, and 505 are all amino acid residues; SARS-8 variant... CoV-2 has the following amino acid residues: aspartic acid at position 339, phenylalanine at position 371, proline at position 373, phenylalanine at position 375, alanine at position 376, aspartic acid at position 405, serine at position 408, and aspartic acid at position 417. The amino acid residues at positions 440, 477, 478, 484, 493, 498, 501, and 505 are all amino acid residues.

11. The pharmaceutical composition for treating novel coronavirus infection as claimed in claim 9 is an aqueous solution containing the above-mentioned peptide.

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