Antibacterial peptide and application thereof in preparation of antibacterial drugs

Abstract

The application belongs to the technical field of antibacterial active peptides, and particularly relates to antibacterial peptides and application thereof in preparation of antibacterial drugs. The antibacterial peptides are not prone to drug resistance, and are the most promising antibiotic substitutes. The application provides antibacterial peptides-1 to antibacterial peptides-20 and derivative sequences thereof, the sequences of which are shown in SEQ ID NO. 1 to 19. The antibacterial peptides can exhibit good antibacterial (bacteria or fungi) activity, and can be applied to treatment of infectious diseases caused by bacteria or fungi. In combination with factors such as hemolytic activity, cytotoxicity, cell membrane permeability and cell drug resistance, the antibacterial peptides such as the derivative of antibacterial peptide-2 and antibacterial peptide-20 have better antibacterial activity on bacteria and fungi, and are expected to be applied to development of clinical antibacterial drugs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of antibacterial active peptides, and particularly relates to an antibacterial peptide and application thereof in preparation of antibacterial drugs. BACKGROUND

[0002] The information disclosed in the background of the present application is only intended to increase the understanding of the overall background of the present application, and should not necessarily be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

[0003] Antibiotic-resistant bacterial and fungal infections have become a major challenge in the field of global public health, seriously threatening human health. With the widespread use of antibiotics in the clinic, the continuous emergence of drug-resistant strains has evolved into a worldwide problem, and the severe situation makes it particularly urgent to develop new antibacterial drugs.

[0004] Antibacterial peptides are short peptides composed of no more than 50 amino acids, with amphiphilic characteristics, and usually have a net positive charge of +2 to +9 under physiological conditions. According to structural characteristics, antibacterial peptides can be mainly divided into four categories: including alpha-helix linear polypeptides, beta-sheet polypeptides with disulfide bonds, cyclic peptides, and polypeptides with flexible structures. This kind of substance mainly exerts antibacterial effect by acting on the cell membrane, and four models of membrane perturbation induced by antibacterial peptides have been reported, including binding to intracellular targets (such as nucleic acids or proteins), polypeptide insertion into the cell membrane to induce micelles, polypeptide parallel combination with the cell membrane to distort the arrangement of lipid polar groups, and polypeptide perpendicular to the membrane to induce the formation of a ring-shaped channel.

[0005] As a potential substitute for antibiotics, antibacterial peptides exhibit significant advantages: not only have broad-spectrum antibacterial activity, but also can effectively kill a variety of bacteria and fungi, and the speed of pathogen resistance to them is much lower than that of traditional antibiotics. These characteristics make antibacterial peptides an important supplement to the existing antibiotic system, and provide a new solution to the increasingly severe drug resistance problem. Therefore, the research and development of antibacterial peptides have important clinical application prospects. SUMMARY

[0006] Therefore, the present application provides a variety of antibacterial peptides and application thereof in preparation of antibacterial drugs. The antibacterial peptides of the present application are antibacterial peptides with good antibacterial activity, which can inhibit infections caused by clinically common bacteria or fungi, and reduce bacterial or fungal resistance caused by antibacterial drugs.

[0007] In order to achieve the above purpose, the present application is realized by the following technical scheme:

[0008] In a first aspect, the present application provides 19 kinds of antibacterial peptides, which have the following sequences:

[0009] (1) the amino acid sequence represented by any one of SEQ ID NO. 1 to 19;

[0010] (2) a derivative polypeptide of the sequence represented by SEQ ID NO. 1 to 19 with one or more amino acid additions, substitutions or deletions, which has substantially the same physiological activity as the antibacterial peptide represented by (1) above.

[0011] The 19 antibacterial peptides are named and have the following specific sequences ("bip" means (S)-3-([1,1'-biphenyl]-4-yl)-2-aminopropanoic acid. "(P)" means phosphorylation modification):

[0012] Antibacterial peptide-1: P-R-V-R-F-S-A-G-P-G-R-A-V-A-W-R-NH2 (SEQ ID NO. 1);

[0013] Antibacterial peptide-2: R-I-H-L-F-K-T-F-S-K-V-Q-K-G-I-L-F-NH2 (SEQ ID NO. 2);

[0014] Antibacterial peptide-2-2bip: R-(Bip)-H-L-F-K-T-F-S-K-V-Q-K-G-I-L-F-NH2 (SEQ ID NO. 3);

[0015] Antibacterial peptide-2-4bip: R-I-H-(Bip)-F-K-T-F-S-K-V-Q-K-G-I-L-F-NH2 (SEQ ID NO. 4);

[0016] Antibacterial peptide-2-2bip-9p: R-(Bip)-H-L-F-K-T-F-S(P)-K-V-Q-K-G-I-L-F-NH2 (SEQ ID NO. 5);

[0017] Antibacterial peptide-2-4bip-9p: R-I-H-(Bip)-F-K-T-F-S(P)-K-V-Q-K-G-I-L-F-NH2 (SEQ ID NO. 6);

[0018] Antibacterial peptide-3: Y-L-L-I-S-L-L-F-L-R-NH2 (SEQ ID NO. 7);

[0019] Antibacterial peptide-4: W-F-L-A-K-I-G-S-V-R-L-NH2 (SEQ ID NO. 8);

[0020] Antimicrobial peptide-5: W-H-L-K-I-Y-K-A-L-I-T-W-A-NH2 (SEQ ID NO. 9);

[0021] Antimicrobial peptide-7: G-F-L-R-L-P-F-A-I-W-NH2 (SEQ ID NO. 10);

[0022] Antimicrobial peptide-8: F-S-L-A-G-I-S-L-A-L-R-A-L-R-S-L-A-A-NH2 (SEQ ID NO. 11);

[0023] Antimicrobial peptide-9: G-K-M-S-L-I-I-N-G-M-A-R-I-L-F-NH2 (SEQ ID NO. 12);

[0024] Antimicrobial peptide-11: I-F-S-I-K-K-F-V-L-NH2 (SEQ ID NO. 13);

[0025] Antimicrobial peptide-19: F-F-L-I-K-K-I-V-F-T-NH2 (SEQ ID NO. 14);

[0026] Antimicrobial peptide-20: L-Q-L-R-R-S-S-I-I-K-W-I-R-NH2 (SEQ ID NO. 15);

[0027] Antimicrobial peptide-20-1bip: (Bip)-Q-L-R-R-S-S-I-I-K-W-I-R-NH2 (SEQ ID NO. 16);

[0028] Antimicrobial peptide-20-3bip: L-Q-(Bip)-R-R-S-S-I-I-K-W-I-R-NH2 (SEQ ID NO. 17);

[0029] Antimicrobial peptide-20-1bip-7p: (Bip)-Q-L-R-R-S-S(P)-I-I-K-W-I-R-NH2 (SEQ ID NO. 18);

[0030] Antimicrobial peptide-20-3bip-7p: L-Q-(Bip)-R-R-S-S(P)-I-I-K-W-I-R-NH2 (SEQ ID NO. 19).

[0031] Among them, the antibacterial peptide-2 is modified by bip or phosphorylation to obtain antibacterial peptide-2-2bip, antibacterial peptide-2-4bip, antibacterial peptide-2-2bip-9p, antibacterial peptide-2-4bip-9p; the antibacterial peptide-20 is modified by bip or phosphorylation to obtain antibacterial peptide-20-1bip, antibacterial peptide-20-3bip, antibacterial peptide-20-1bip-7p, antibacterial peptide-20-3bip-7p. The nineteen kinds of antibacterial peptides shown above exhibit good antibacterial activity, combined with hemolytic activity, cytotoxicity, cell membrane permeability, cell drug resistance and other factors, among which the corresponding derivative peptides of antibacterial peptide-2 and antibacterial peptide-20 have more excellent bacteriostatic effect and higher safety.

[0032] In the above (2), the "one or more" can be any integer from 1 to 3, and the addition, deletion or substitution can occur at the N-terminus, C-terminus or sequence of the amino acid sequence shown in SEQ ID NO: 1-19, and the derived polypeptide formed should have a similarity of 95% or more with the amino acid sequence of SEQ ID NO: 1-19, and the similar alignment method is the Blast method. In addition, the derived polypeptide should have substantially similar antibacterial activity to the antibacterial peptide shown in (1).

[0033] In a second aspect, the present application provides a fusion protein, which is connected by a first domain and a second domain, the first domain is the antibacterial peptide of the first aspect, and the second domain is an effector group.

[0034] The first and second domains are connected by a covalent bond, and the order of connection is not limited; the effector group includes a fragment for prolonging the in vivo half-life, a fragment for improving the target cell binding effect, or a fragment for improving the transmembrane performance of the antibacterial peptide.

[0035] Preferably, the fragment for prolonging the in vivo half-life is one of serum albumin or its fragment, polyethylene glycol, a domain binding serum albumin (such as anti-serum albumin single domain antibody), polyethylene glycol-liposome complex.

[0036] Preferably, the fragment for improving the target cell binding effect is, for example, an aptamer or a fragment with target binding activity based on the antigen-antibody binding effect.

[0037] Preferably, the fragment for improving the transmembrane performance of the antibacterial peptide is a cell-penetrating peptide, such as TAT (trans-activator of transcription cell-penetrating peptide), Penetratin (penetrating peptide), Arginine-rich peptides (arginine-rich cell-penetrating peptide), etc.

[0038] In a third aspect, the present application provides a pharmaceutical composition comprising the antibacterial peptide of the first aspect or the fusion protein of the second aspect, and a pharmaceutically acceptable carrier.

[0039] The above-mentioned carriers can be at least one of buffers (acetate, Tris (tris(hydroxymethyl) aminomethane), phosphate, citrate or other organic acids), antioxidants (such as ascorbic acid and methionine), preservatives (such as chloro-octadecyl dimethyl benzyl ammonium, butanol or benzyl alcohol, methyl paraben, propyl paraben, catechol, resorcinol, cyclohexanol, 3-pentanol or m-cresol), bactericides (such as chlorhexidine, benzalkonium chloride, benzethonium chloride), proteins (such as serum albumin, gelatin or immunoglobulin), hydrophilic polymers (such as polyvinylpyrrolidone), amino acids (such as glycine, glutamine, asparagine, histidine, arginine or lysine), carbohydrates (including glucose, mannose, dextrin, sucrose, mannitol, trehalose or sorbitol), chelating agents (such as EDTA (ethylenediaminetetraacetic acid)), tonicity adjusting agents (such as trehalose or sodium chloride), surfactants (such as polysorbate, Tween ® , PLURONICS ® or polyethylene glycol), salt-forming counterions (such as sodium ions), metal complexes (such as Zn-protein complexes).

[0040] In a fourth aspect, the present application provides a pharmaceutical preparation for antibacterial, comprising the above-mentioned antibacterial peptide, fusion protein or pharmaceutical composition.

[0041] Preferably, the antibacterial peptide, fusion protein or pharmaceutical composition in the preparation can be 0.01-99%, 0.1-70%, 1-30%, 0.01-0.05%, 0.05-0.1%, 0.1-0.3%, 0.3-0.5%, 0.5-1%, 1-3%, 3-5%, 5-10%, 10-20%, 20-30%, 30-50%, 50-70% or 70-99% of the total mass of the pharmaceutical preparation.

[0042] Preferably, the preparation is an oral preparation or an injection.

[0043] In a fifth aspect, the present application provides the use of the antibacterial peptide of the first aspect, the fusion protein of the second aspect or the pharmaceutical composition of the third aspect in the preparation of an antibacterial drug.

[0044] Further, the above-mentioned antibacterial drug is a drug for preventing, improving or treating diseases related to fungal or bacterial infection.

[0045] The fungus is pathogenic Candida, preferably the fungus is selected from one or more of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida auris.

[0046] The bacteria is gram-positive bacteria or gram-negative bacteria, preferably the bacteria is selected from one or more of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii.

[0047] Further, the use of the antimicrobial peptide-1, the fusion protein comprising the antimicrobial peptide-1 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0048] Preferably, the use of the antimicrobial peptide-1, the fusion protein comprising the antimicrobial peptide-1 or the pharmaceutical composition in the preparation of an anti-gram-positive bacteria drug; the gram-positive bacteria is Staphylococcus aureus.

[0049] Further, the use of the antimicrobial peptide-2, the fusion protein comprising the antimicrobial peptide-2 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0050] Preferably, the use of the antimicrobial peptide-2, the fusion protein comprising the antimicrobial peptide-2 or the pharmaceutical composition in the preparation of an anti-gram-positive bacteria or gram-negative bacteria, anti-Candida drug; the gram-positive bacteria or gram-negative bacteria is at least one of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and the Candida is at least one of Candida glabrata and Candida tropicalis.

[0051] Further, the use of the antimicrobial peptide-2-2bip, the fusion protein comprising the antimicrobial peptide-2-2bip or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0052] Preferably, the use of the antimicrobial peptide-2-2bip, the fusion protein comprising the antimicrobial peptide-2-2bip or the pharmaceutical composition in the preparation of an anti-gram-positive bacteria or gram-negative bacteria, anti-Candida drug; the gram-positive bacteria or gram-negative bacteria is at least one of Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; and the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0053] Further, the use of the antimicrobial peptide-2-4bip, the fusion protein comprising the antimicrobial peptide-2-4bip or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0054] Preferably, the use of the antibacterial peptide-2-4bip, the fusion protein comprising the antibacterial peptide-2-4bip or the pharmaceutical composition in the preparation of an antibacterial drug against at least one of Gram-positive bacteria or Gram-negative bacteria; the Gram-positive bacteria or Gram-negative bacteria are at least one of Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0055] Further, the use of the antibacterial peptide-2-2bip-9p, the fusion protein comprising the antibacterial peptide-2-2bip-9p or the pharmaceutical composition in the preparation of an antibacterial drug.

[0056] Preferably, the use of the antibacterial peptide-2-2bip-9p, the fusion protein comprising the antibacterial peptide-2-2bip-9p or the pharmaceutical composition in the preparation of an antibacterial drug against at least one of Gram-positive bacteria or Gram-negative bacteria; the Gram-positive bacteria or Gram-negative bacteria are at least one of Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0057] Further, the use of the antibacterial peptide-2-4bip-9p, the fusion protein comprising the antibacterial peptide-2-4bip-9p or the pharmaceutical composition in the preparation of an antibacterial drug.

[0058] Preferably, the use of the antibacterial peptide-2-4bip-9p, the fusion protein comprising the antibacterial peptide-2-4bip-9p or the pharmaceutical composition in the preparation of an antibacterial drug against at least one of Gram-positive bacteria or Gram-negative bacteria; the Gram-positive bacteria or Gram-negative bacteria are at least one of Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0059] Further, the use of the antibacterial peptide-3, the fusion protein comprising the antibacterial peptide-3 or the pharmaceutical composition in the preparation of an antibacterial drug.

[0060] Preferably, the use of the antibacterial peptide-3, the fusion protein comprising the antibacterial peptide-3 or the pharmaceutical composition in the preparation of an antibacterial drug against at least one of Gram-positive bacteria or Gram-negative bacteria; the Gram-positive bacteria or Gram-negative bacteria are at least one of Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0061] Further, the use of the antibacterial peptide-4, the fusion protein comprising the antibacterial peptide-4 or the pharmaceutical composition in the preparation of an antibacterial drug.

[0062] Preferably, the use of the antimicrobial peptide-4, the fusion protein comprising the antimicrobial peptide-4 or the pharmaceutical composition in the preparation of an anti-Gram-positive or Gram-negative bacteria, anti-Candida drug; the Gram-positive or Gram-negative bacteria is Staphylococcus aureus; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0063] Further, the use of the antimicrobial peptide-5, the fusion protein comprising the antimicrobial peptide-5 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0064] Preferably, the use of the antimicrobial peptide-5, the fusion protein comprising the antimicrobial peptide-5 or the pharmaceutical composition in the preparation of an anti-Gram-positive or Gram-negative bacteria, anti-Candida drug; the Gram-positive or Gram-negative bacteria is Staphylococcus aureus; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0065] Further, the use of the antimicrobial peptide-7, the fusion protein comprising the antimicrobial peptide-7 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0066] Preferably, the use of the antimicrobial peptide-7, the fusion protein comprising the antimicrobial peptide-7 or the pharmaceutical composition in the preparation of an anti-Gram-positive or Gram-negative bacteria, anti-Candida drug; the Gram-positive or Gram-negative bacteria is Staphylococcus aureus; the Candida is Candida tropicalis.

[0067] Further, the use of the antimicrobial peptide-8, the fusion protein comprising the antimicrobial peptide-8 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0068] Preferably, the use of the antimicrobial peptide-8, the fusion protein comprising the antimicrobial peptide-8 or the pharmaceutical composition in the preparation of an anti-Gram-positive or Gram-negative bacteria, anti-Candida drug; the Gram-positive or Gram-negative bacteria is at least one of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis.

[0069] Further, the use of the antimicrobial peptide-9, the fusion protein comprising the antimicrobial peptide-9 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0070] Preferably, the use of the antimicrobial peptide-9, the fusion protein comprising the antimicrobial peptide-9 or the pharmaceutical composition in the preparation of an anti-Candida drug; the Candida is Candida tropicalis.

[0071] Further, the use of the antimicrobial peptide-11, the fusion protein comprising the antimicrobial peptide-11 or the pharmaceutical composition in the preparation of an antimicrobial drug.

[0072] Preferably, the use of the antimicrobial peptide-11, the fusion protein comprising the antimicrobial peptide-11 or the pharmaceutical composition in the preparation of an antibacterial drug against Gram-positive bacteria or Gram-negative bacteria; the Gram-positive bacteria or Gram-negative bacteria is Staphylococcus aureus.

[0073] Further, the use of the antimicrobial peptide-19, the fusion protein comprising the antimicrobial peptide-19 or the pharmaceutical composition in the preparation of an antibacterial drug.

[0074] Preferably, the use of the antimicrobial peptide-19, the fusion protein comprising the antimicrobial peptide-19 or the pharmaceutical composition in the preparation of an antibacterial drug against Gram-positive bacteria or Gram-negative bacteria, Candida; the Gram-positive bacteria or Gram-negative bacteria is Staphylococcus aureus; the Candida is Candida tropicalis.

[0075] Further, the use of the antimicrobial peptide-20, the fusion protein comprising the antimicrobial peptide-20 or the pharmaceutical composition in the preparation of an antibacterial drug.

[0076] Preferably, the use of the antimicrobial peptide-20, the fusion protein comprising the antimicrobial peptide-20 or the pharmaceutical composition in the preparation of an antibacterial drug against Gram-positive bacteria or Gram-negative bacteria, Candida; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis; the Gram-positive bacteria or Gram-negative bacteria is at least one of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii.

[0077] Further, the use of the antimicrobial peptide-20-1bip, the fusion protein comprising the antimicrobial peptide-20-1bip or the pharmaceutical composition in the preparation of an antibacterial drug.

[0078] Preferably, the use of the antimicrobial peptide-20-1bip, the fusion protein comprising the antimicrobial peptide-20-1bip or the pharmaceutical composition in the preparation of an antibacterial drug against Gram-positive bacteria or Gram-negative bacteria, Candida; the Gram-positive bacteria or Gram-negative bacteria is Pseudomonas aeruginosa; the Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0079] Further, the use of the antimicrobial peptide-20-3bip, the fusion protein comprising the antimicrobial peptide-20-3bip or the pharmaceutical composition in the preparation of an antibacterial drug.

[0080] Preferably, the antibacterial peptide-20-3bip, the fusion protein comprising the antibacterial peptide-20-3bip or the pharmaceutical composition is used in the preparation of an antibacterial drug against at least one of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Acinetobacter baumannii; or against at least one of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis.

[0081] Further, the antibacterial peptide-20-1bip-7p, the fusion protein comprising the antibacterial peptide-20-1bip-7p or the pharmaceutical composition is used in the preparation of an antibacterial drug.

[0082] Preferably, the antibacterial peptide-20-1bip-7p, the fusion protein comprising the antibacterial peptide-20-1bip-7p or the pharmaceutical composition is used in the preparation of an antibacterial drug against at least one of Klebsiella, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii; or against at least one of Candida albicans, Candida tropicalis, Candida parapsilosis.

[0083] Further, the antibacterial peptide-20-3bip-7p, the fusion protein comprising the antibacterial peptide-20-3bip-7p or the pharmaceutical composition is used in the preparation of an antibacterial drug.

[0084] Preferably, the antibacterial peptide-20-3bip-7p, the fusion protein comprising the antibacterial peptide-20-3bip-7p or the pharmaceutical composition is used in the preparation of an antibacterial drug against at least one of Klebsiella, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii; or against at least one of Candida albicans, Candida parapsilosis, Candida tropicalis.

[0085] A specific embodiment of the above-mentioned use is that the antibacterial peptide-2, the antibacterial peptide-20 and the derivative peptides thereof, and the fusion protein or the pharmaceutical composition thereof are used in the preparation of a drug for gram-positive bacteria or gram-negative bacteria related infection.

[0086] Another specific embodiment is that the antibacterial peptide-2, the antibacterial peptide-20 and the derivative peptides thereof, and the fusion protein or the pharmaceutical composition thereof are used in the preparation of a drug for Candida related infection.

[0087] Further, the antibacterial peptide is selected from antibacterial peptide-2, antibacterial peptide-20, antibacterial peptide-2-2bip, antibacterial peptide-2-4bip, antibacterial peptide-2-2bip-9p, antibacterial peptide-2-4bip-9p; the antibacterial peptide-20 derivative peptide is antibacterial peptide-20-1bip, antibacterial peptide-20-3bip, antibacterial peptide-20-1bip-7p, antibacterial peptide-20-3bip-7p.

[0088] In a sixth aspect, the present application provides a composition comprising the antibacterial peptide of the first aspect and caspofungin.

[0089] Preferably, the mass ratio of the antibacterial peptide and caspofungin is 0.04-1:1; more preferably 0.04-0.2:1.

[0090] In a seventh aspect, the present application provides use of the composition of the sixth aspect in the preparation of an antifungal drug.

[0091] Further, the fungus is pathogenic Candida; the pathogenic Candida is at least one of Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis.

[0092] Further, the antibacterial peptide is selected from antibacterial peptide-2, antibacterial peptide-20, antibacterial peptide-2-2bip, antibacterial peptide-2-4bip, antibacterial peptide-2-2bip-9p, antibacterial peptide-2-4bip-9p; the antibacterial peptide-20 derivative peptide is antibacterial peptide-20-1bip, antibacterial peptide-20-3bip, antibacterial peptide-20-1bip-7p, antibacterial peptide-20-3bip-7p.

[0093] Compared with the prior art, the present application has the following beneficial effects:

[0094] (1) The antibacterial peptides provided by the present application are all within 30 amino acids in length, can be conveniently prepared based on a chemical synthesis method, and have amino modification at the end of the peptide chain, good water solubility, and better processing performance.

[0095] (2) The performance of the above antibacterial peptides is verified from antibacterial activity, hemolytic activity, cytotoxicity, and the like. The antibacterial peptides provided by the present application have good bacteriostatic effect, and have lower toxicity to normal cells. Further, the above peptides show lower hemolytic activity at a therapeutic dose, are safer for clinical drug application, and have good antibacterial activity in combination with low-concentration caspofungin. BRIEF DESCRIPTION OF DRAWINGS

[0096] The drawings constituting a part of the specification of the present application serve to provide further understanding of the present application, and the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0097] Figure 1 Figure for hemolytic activity detection results of unmodified antibacterial peptide in Example 3;

[0098] Figure 2 Figure for hemolytic activity detection results of modified antibacterial peptide in Example 3;

[0099] Figure 3 Figure for mouse survival curve of mice infected with Candida albicans by polypeptide combined with caspofungin;

[0100] Figure 4 Figure for kidney fungal load of mice infected with Candida albicans by polypeptide combined with caspofungin;

[0101] Figure 5 Figure for mouse survival curve of mice infected with Candida auris by polypeptide combined with caspofungin;

[0102] Figure 6 Figure for kidney fungal load of mice infected with Candida auris by polypeptide combined with caspofungin. DETAILED DESCRIPTION

[0103] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0104] In order to enable persons skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application are described in detail below in combination with examples. The reagents and apparatus information involved in the following examples are as follows:

[0105] 1. Strains

[0106] 1) Fungi:

[0107] Candida albicans SC5314;

[0108] Candida glabrata CG9, the strain was from Jinan Central Hospital;

[0109] Candida tropicalis CT2, the strain was from Jinan Central Hospital;

[0110] Candida parapsilosis CP1, the strain was from Jinan Central Hospital;

[0111] Candida auris CBS12774, the strain was a gift from Dr. Fang Wenjie of the Second Military Medical University of the People's Liberation Army.

[0112] 2) Bacteria:

[0113] Staphylococcus aureus ATCC29213;

[0114] Pseudomonas aeruginosa GD001, the strain was given by Dr. Wenchang Yuan of Guangzhou Medical University;

[0115] Klebsiella GD002, the strain was given by Dr. Wenchang Yuan of Guangzhou Medical University;

[0116] Acinetobacter baumannii GD003, the above strains were given by Dr. Wenchang Yuan of Guangzhou Medical University;

[0117] Escherichia coli GD004, the above strains were given by Dr. Wenchang Yuan of Guangzhou Medical University.

[0118] 2. Culture medium

[0119] 1) YPD liquid medium:

[0120] 8 g of proteose peptone, 8 g of glucose, 4 g of yeast extract, and 400 mL of triple distilled water were added to make up the volume, and sterilized by high pressure sterilization (121℃, 20 min) and stored at 4℃ for standby use.

[0121] 2) YPD solid medium:

[0122] 8 g of proteose peptone, 8 g of glucose, 4 g of yeast extract, and 8 g of agar were added to make up the volume, and sterilized by high pressure sterilization (121℃, 20 min) and stored at 4℃ for standby use.

[0123] 3) RPMI 1640 liquid medium:

[0124] 10 g of RPMI 1640 solid powder, 2.0 g of NaHCO3, and 34.5 g of morpholine propanesulfonic acid were dissolved in 900 mL of triple distilled water, adjusted to pH 7.0 (25℃) with 1 M NaOH, made up to 1000 mL with triple distilled water, filtered with a 0.22 μm microporous filter to remove bacteria, and stored at 4℃ for standby use after dispensing.

[0125] 4) LB solid medium:

[0126] 10 g of LB medium powder and 8 g of agar were added to make up the volume, and sterilized by high pressure sterilization (121℃, 20 min) and stored at 4℃ for standby use.

[0127] 5) LB liquid medium:

[0128] 10 g of LB medium powder was added to make up the volume, and sterilized by high pressure sterilization (121℃, 20 min) and stored at 4℃ for standby use.

[0129] 6) MHB liquid medium:

[0130] MHB medium powder 8.4 g, add triple distilled water to 400 mL, after high pressure sterilization (121℃, 20 min), store at 4℃ for standby.

[0131] 7) RPMI 1640 cell culture solution (Wuhan Procell).

[0132] 3. Instruments and equipment

[0133] SW-CJ-JC double single-sided super-clean workbench (Suzhou Purification Equipment Co., Ltd.); NBS Innova 42 constant temperature shaker (Germany eppendorf product); Centrifuge 5424R centrifuge (Germany eppendorf product); SHP-250 biochemical incubator (Shanghai Jinghong Experimental Equipment Co., Ltd.); MLS-3750 high-pressure steam sterilization pot (Japan SANYO product); UV2450 ultraviolet visible spectrophotometer (Japan Shimadzu product); Model 680 multifunctional enzyme label instrument (American BIO-RAD product); SPX biochemical incubator (Ningbo Jiangnan Instrument Factory); 3111 carbon dioxide cell incubator (American Thermo product); LSM900 confocal microscope (Germany Zeiss product); EM UC7 ultrathin microtome (Germany LEICA product); Hitachi-HT7700 transmission electron microscope (Japan Hitachi product).

[0134] Example 1 Artificial synthesis of antibacterial peptide

[0135] This example is based on the transcriptome data of fungal and host interaction to obtain a large number of candidate polypeptides, and the 20 polypeptide sequences are obtained by scoring through multiple evaluation models, which are named as antibacterial peptide-1 to antibacterial peptide-20 in turn. After preliminary activity screening, polypeptides with further application potential are selected for modification, and four modified polypeptides are obtained, which show good antibacterial activity. The number and sequence of the 28 polypeptides are shown in Table 1 as follows:

[0136] Table 1 28 polypeptides synthesized by artificial synthesis

[0137]

[0138] The above antibacterial peptide-1~antibacterial peptide-20 is obtained by artificial synthesis. The polypeptide synthesis adopts Fmoc solid phase synthesis method, and the peptide segment is synthesized according to the amino acid sequence. After cutting, precipitation and purification, the powder-like polypeptide is obtained. The synthesis process is entrusted to Guoping Pharmaceutical Co., Ltd.

[0139] Example 2 Detection of antibacterial activity of antibacterial peptide

[0140] 1. Reagents

[0141] The antibacterial peptides were stored at -20 °C. Before the experiment, the antibacterial peptides were dissolved in sterile water to a concentration of 10 mM stock solution.

[0142] 2. Experimental method

[0143] (1) Antifungal activity determination method:

[0144] According to the Clinical and Laboratory Standards Institute (CLSI) M27-A3 document, the minimum inhibitory concentration (MIC) of the polypeptide on different fungal strains was determined by micro-broth dilution method 80 ). The fungal strains were activated from the stock tube to YPD solid plate by streaking method, and activated at least once to ensure the strain activity, and a single colony was picked up from the activated plate to 1 mL YPD liquid medium, and cultured at 30 °C, 200 rpm for 12 h until the growth reached the logarithmic phase. The experimental strains grown in the logarithmic phase were centrifuged and washed with PBS buffer to remove the culture medium, and the OD value was determined by spectrophotometer to determine the cell density and diluted to 1×10 3 cells / mL with RPMI1640 medium. The bacterial solution was added to a 96-well sterile microplate, and the test drug was added by double dilution method and mixed well, and the negative control was not added with the drug, and the positive control was added with fluconazole, and the blank control well was added with only RPMI1640 medium, and three parallel groups were set. The well plate was placed in a 35 °C incubator and incubated for 24 h, and the results were determined by visual observation method, and the minimum drug concentration that could inhibit 80% of fungal growth was the final result MIC 80 value.

[0145] (2) Antimicrobial activity determination method:

[0146] According to the Clinical and Laboratory Standards Institute (CLSI) M100-S31 document, the minimum inhibitory concentration (MIC) of the polypeptide on different bacterial strains was determined by micro-broth dilution method 80 ). The bacterial strains were activated from the stock tube to LB solid plate by streaking method, and activated at least once to ensure the strain activity, and a single colony was picked up from the activated plate to 1 mL LB liquid medium, and cultured at 37 °C, 200 rpm for 12 h until the growth reached the logarithmic phase. The experimental strains grown in the logarithmic phase were centrifuged and washed with PBS buffer to remove the culture medium, and the OD value was determined by spectrophotometer to determine the cell density and diluted to 5×10 5cells / mL. The bacterial solution was added to 96 sterile microplates, and the test drugs were added by the double dilution method and mixed well. The negative control was without the test drugs, and the blank control was only with MHB medium. Each group had three replicates. The plates were placed in a 37°C incubator for 24 h. The results were determined by visual observation, and the minimum drug concentration that inhibited 80% of bacterial growth was the final MIC value. 80

[0147] (3) Drug combination experiment:

[0148] The experimental strain grown in the logarithmic phase was centrifuged and washed with PBS buffer to remove the culture medium. The cell density was determined by spectrophotometry, and the cells were diluted to 1×10 3 cells / mL with RPMI1640 medium. The working solutions of different drug concentrations of the antibacterial peptide and caspofungin were prepared with the diluted bacterial solution. In the 96-well plate, columns 1-11 were set with different concentrations of antibacterial peptide working solutions, and rows A-G were set with different concentrations of caspofungin working solutions. The blank bacterial solution was added to columns 12 and row H. The plates were placed in a 35°C incubator for 24 h. The OD value of each well was detected at 600 nm, and the control wells were blank wells without the addition of drugs. The growth rate of each well = drug-added well value / control well x 100%. The control well had a growth rate of 100%, and the drug concentration of the well with an absorbance decrease of 80% compared to the control well was identified as the MIC. The calculation and analysis of the combined antibacterial index (FICI) were used to determine whether there was a synergistic effect between the drugs. When FICI≤0.5, the interaction was considered to be synergistic (SYN), when FICI>0.5 and≤1, it was considered to be additive (ADD), and when FICI>1, it was considered to have no interaction (IND).

[0149] 3. Experimental results:

[0150] Table 2 Antifungal activity of antibacterial peptide

[0151]

[0152] ​As can be seen from Table 2, the antibacterial peptide-2 has a significant inhibitory effect on Candida glabrata and Candida tropicalis; the antibacterial peptide-2-2bip and the antibacterial peptide-2-4bip have a significant inhibitory effect on pathogenic Candida (Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis); the antibacterial peptide-2-2bip-9p has a significant inhibitory effect on Candida glabrata, Candida albicans, and Candida tropicalis; the antibacterial peptide-7 has a significant inhibitory effect on Candida tropicalis; the antibacterial peptide-4 and the antibacterial peptide-5 have a significant inhibitory effect on pathogenic Candida (Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis); the antibacterial peptide-8 has a significant inhibitory effect on Candida albicans, Candida glabrata, and Candida tropicalis; the antibacterial peptide-9 and the antibacterial peptide-19 have a significant inhibitory effect on Candida tropicalis; the antibacterial peptide-20 has a significant inhibitory effect on Candida albicans, Candida glabrata, and Candida tropicalis; the antibacterial peptide-20-1bip and the antibacterial peptide-20-3bip have a significant inhibitory effect on pathogenic Candida (Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis); the antibacterial peptide-20-1bip-7p and the antibacterial peptide-20-3bip-7p have a significant inhibitory effect on Candida albicans, Candida tropicalis, and Candida parapsilosis.

[0153] The antibacterial peptide-1, the antibacterial peptide-2-4bip-9p, the antibacterial peptide-3, the antibacterial peptide-6, the antibacterial peptide-10, the antibacterial peptide-11, the antibacterial peptide-12, the antibacterial peptide-13, the antibacterial peptide-14, the antibacterial peptide-15, the antibacterial peptide-16, the antibacterial peptide-17, the antibacterial peptide-18, and the antibacterial peptide-18 do not exhibit antifungal activity.

[0154] Among them, the antibacterial peptide-2 and all its derivative peptides, the antibacterial peptide-20 and all its derivative peptides, and the antibacterial peptide-5 exhibit better antifungal activity. Further antibacterial activity tests were conducted on the above antibacterial peptides, and their antifungal activity in combination with caspofungin was tested, and the results are as follows:

[0155] Table 3: Results of antibacterial peptide antibacterial activity determination

[0156]

[0157] Table 4: Results of antibacterial peptide caspofungin combination antifungal activity test

[0158]

[0159] As can be seen from Table 3, in the antibacterial activity against gram-negative / positive bacteria, all the antibacterial peptides exhibit different antibacterial activities. Among them, antibacterial peptide-1, antibacterial peptide-4, antibacterial peptide-5, antibacterial peptide-7, antibacterial peptide-11 and antibacterial peptide-19 have significant inhibitory effect on Staphylococcus aureus; antibacterial peptide-2-2bip, antibacterial peptide-2-4bip and antibacterial peptide-2-2bip-9p have significant inhibitory effect on Escherichia coli, Pseudomonas aeruginosa, Klebsiella and Acinetobacter baumannii; antibacterial peptide-2 has significant inhibitory effect on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii; antibacterial peptide-2-4bip-9p has significant inhibitory effect on Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii; antibacterial peptide-3 has significant inhibitory effect on Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii; antibacterial peptide-8 has significant inhibitory effect on Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Staphylococcus aureus; antibacterial peptide-20 has significant inhibitory effect on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii; antibacterial peptide-20-3bip, antibacterial peptide-20-1bip-7p and antibacterial peptide-20-3bip-7p have significant inhibitory effect on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella and Acinetobacter baumannii; antibacterial peptide-20-1bip has significant inhibitory effect on Pseudomonas aeruginosa. The rest of the antibacterial peptides do not show antibacterial activity against gram-negative / positive bacteria. It can be seen that the derived peptides of antibacterial peptide-2 and antibacterial peptide-20, antibacterial peptide-3 and antibacterial peptide-8 have better antibacterial activity and have significant inhibitory effect on gram-negative / positive bacteria.

[0160] Antibacterial peptide-2-2bip-9p, antibacterial peptide-2-4bip-9p, antibacterial peptide-20-1bip-7p and antibacterial peptide-20-3bip-7p have synergistic effect with caspofungin, as shown in Table 4. When antibacterial peptide-2-2bip-9p, antibacterial peptide-2-4bip-9p, antibacterial peptide-20-1bip-7p and antibacterial peptide-20-3bip-7p are combined with caspofungin, the FICI is less than 0.5 (except for Candida parapsilosis when antibacterial peptide-2-4bip-9p and antibacterial peptide-20-1bip-7p are combined with caspofungin). And by the same way, antibacterial peptide-2, antibacterial peptide-2-2bip, antibacterial peptide-2-4bip, antibacterial peptide-20, antibacterial peptide-20-1bip and antibacterial peptide-20-3bip are combined with caspofungin to test the antifungal activity, all of them exhibit significant inhibitory activity, and the FICI value is less than 0.5, which has synergistic effect.

[0161] It can be seen that the antibacterial peptides of the application can be used in combination with the existing known antibacterial drugs and exhibit better synergistic effect.

[0162] Example 3 Detection of hemolytic activity of antibacterial peptides

[0163] This example is used to detect the hemolytic activity of the polypeptides showing good antibacterial activity in Example 2 on red blood cells.

[0164] 1. Reagents

[0165] The antibacterial peptide powder was stored at -20 °C. Before the experiment, the antibacterial peptide was dissolved in sterile water to a 10 mM stock solution.

[0166] 2. Animals

[0167] SD rats were purchased from Weitong Life Science Center.

[0168] 3. Experimental method

[0169] Blood was taken from the abdominal aorta of SD rats into a blood collection tube containing sodium heparin anticoagulant, centrifuged at 4 °C and 3000 rpm for 10 minutes, the supernatant was discarded, washed three times with physiological saline, and the supernatant was discarded to obtain a 100% red blood cell solution. The red blood cell solution (10%) used in the experiment was obtained by diluting the physiological saline to 10%. The antibacterial peptide was dissolved in physiological saline using the double dilution method, with the highest concentration being 400 μM solution and the lowest concentration being 3.125 μM. The final system was 100 μL. The negative control was only added with 100 μL of physiological saline, and the positive control was added with 100 μL of 1% Triton X-100. Three sets of parallel samples were set for each sample. 100 μL of 10% red blood cell solution was added to the above solutions (at this time the drug concentration was halved). The samples were incubated at 37 °C and 200 rpm for 1 h. After incubation, all samples were centrifuged at 4 °C and 3000 rpm for 10 minutes, and 100 μL of supernatant was taken to a 96-well plate and the OD 540 nm value was measured by an enzyme marker.

[0170] Hemolysis rate = (Am-An) / (Ap-An) x 100%

[0171] Am is the OD value of the experimental sample; An is the OD value of the negative control group; Ap is the OD value of the positive control group.

[0172] 4. Experimental results

[0173] Figure 1 Figure for the hemolytic activity detection results of the unmodified antibacterial peptide in Example 3; Figure 2 Figure for the hemolytic activity detection results of the modified antibacterial peptide in Example 3. From Figures 1-2It can be seen that in the unmodified polypeptides, the antibacterial peptide-2, antibacterial peptide-7, antibacterial peptide-19 show lower hemolytic activity, in which antibacterial peptide-2 and antibacterial peptide-7 have the lowest hemolysis rate and have higher safety. In the modified polypeptides, the hemolysis rate of the rest of the polypeptides is lower except for antibacterial peptide-2-2bip, antibacterial peptide-2-4bip-9p, and the safety is relatively high compared with other antifungal polypeptides.

[0174] Example 4 Cell toxicity detection of antibacterial peptides

[0175] In this example, the cell toxicity of the polypeptides showing good antibacterial activity in Example 2 is detected.

[0176] 1. Reagents

[0177] The antibacterial peptide powder is stored at -20 °C. Before the experiment, the antibacterial peptide is dissolved in sterile water to form a 10 mM stock solution.

[0178] 2. Cell lines

[0179] HUVEC human umbilical artery epithelial cells, HEK-293T human embryonic kidney cells

[0180] 3. Experimental method

[0181] The cells in the logarithmic growth phase are trypsinized, and the cell suspension is collected in a sterile centrifuge tube. The cell density is adjusted to 5 x 10 4 cells / mL is inoculated into a 96-well plate and incubated overnight to allow the cells to adhere. The supernatant is replaced with fresh 1640 medium containing different concentrations of antibacterial peptides, and the 96-well plate is placed in a 37 °C incubator containing 5% CO2 for 24 h. After incubation, the cell morphology is observed, and 10 μL of 5 mg / mL MTT solution is added to each well. After 4 hours, the supernatant is discarded, 100 μL of DMSO is added to each well, and the absorbance at 490 nm is measured using a microplate reader.

[0182] 4. Experimental results

[0183] The experimental results are shown in Table 5 below. The antibacterial peptides-2, 4, 7, 19, 20, and the phosphorylated modified derivatives of antibacterial peptides 2 and 20 show good low cytotoxicity characteristics.

[0184] Table 5 Cytotoxicity test of antibacterial peptides

[0185]

[0186] Example 5 Evaluation of the in vivo effect of antibacterial peptides

[0187] This example tests the in vivo therapeutic effect of polypeptide 2-2bip-9p in combination with caspofungin in mice.

[0188] 1. Reagents

[0189] The antibacterial peptide powder, caspofungin (CAS) and amphotericin B (AMB) powder were stored at -20°C. Before the experiment, the antibacterial peptide was dissolved in sterile water to a 10 mM stock solution, and CAS and AMB were dissolved in DMSO.

[0190] 2. Animals

[0191] 6-8 week-old male BALB / c mice were purchased from the Vital River Laboratory Animal Technology Services Co.

[0192] 3. Experimental methods

[0193] In the single drug and combination drug experiments, 6-8 week-old male BALB / c mice were randomly divided into six groups (10 mice per group): polypeptide single drug treatment group, CAS (0.2 mg / kg) single drug treatment group, polypeptide combined CAS treatment group, and AMB, CAS (1 mg / kg) positive control group and PBS negative control group. Mice injected with C. auris were injected with 150 mg / kg of cyclophosphamide inhibitor three days before and one day before injection of the bacteria, and then the overnight activated white Candida SC5314 and C. auris CBS12774 yeast phase cells were adjusted to a concentration of 3.5 x 10 6 cells / mL and 1 x 10 8 cells / mL with sterile saline, and 100 μL of the bacterial suspension was injected into each mouse via the tail vein. After 24 hours of infection, the drug administration regimen was initiated: the polypeptide group was injected intraperitoneally with 5 mg / kg of polypeptide, the CAS group was injected with 0.2 mg / kg of CAS, the combination treatment group was injected with 5 mg / kg of polypeptide and 0.2 mg / kg of CAS simultaneously, and the control group was injected with 10 mg / kg of AMB and 1 mg / kg of CAS, respectively, and the same volume of PBS buffer. The drug was administered once a day for 4 consecutive days. The survival of the mice was observed daily during the treatment period, and the bilateral kidneys were collected after euthanasia on the 4th day: the left kidney was used for histopathological analysis; and the right kidney was used for real-time detection of kidney fungal load.

[0194] 4. Experimental results

[0195] Figure 3 Figure 2 is a graph of the survival curve of mice infected with C. albicans treated with polypeptide in combination with caspofungin; Figure 4 Figure 3 is a graph of the kidney fungal load of mice infected with C. albicans treated with polypeptide in combination with caspofungin; Figure 5 Figure 4 is a graph of the survival curve of mice infected with C. auris treated with polypeptide in combination with caspofungin; Figure 6Figure 6 shows the kidney fungal burden of mice infected with C. albicans and treated with polypeptide and caspofungin. (In the figure, "ns" indicates no significant difference; "***" indicates p < 0.001). The results of the experiment are shown in Figure 6. The body weight change curve of the polypeptide or caspofungin group (0.2 mg / kg) alone showed no significant difference from the PBS group. However, the survival rate of mice in the combination therapy group was significantly improved. Kidney fungal load analysis showed that the pathogenicity of fungi in the combination therapy group was significantly reduced. These findings suggest that the polypeptide-caspofungin combination therapy regimen has important clinical application potential as a fungal infection strategy. P Figures 3-6 The results of the experiment are shown in Figure 6. The body weight change curve of the polypeptide or caspofungin group (0.2 mg / kg) alone showed no significant difference from the PBS group. However, the survival rate of mice in the combination therapy group was significantly improved. Kidney fungal load analysis showed that the pathogenicity of fungi in the combination therapy group was significantly reduced. These findings suggest that the polypeptide-caspofungin combination therapy regimen has important clinical application potential as a fungal infection strategy.

[0196] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. An antimicrobial peptide, characterized in that, The amino acid sequence of the antimicrobial peptide is shown in any one of SEQ ID NO.2-6.

2. A fusion protein, characterized in that, The fusion protein is composed of a first domain and a second domain connected together. The first domain is the antimicrobial peptide of claim 1, and the second domain is an effector group. The first and second domains are connected by covalent bonds. The effector group includes fragments that prolong the in vivo half-life, fragments that improve the binding effect to target cells, or fragments that improve the transmembrane properties of the antimicrobial peptide.

3. The fusion protein as described in claim 2, characterized in that, The fragment used to prolong the in vivo half-life is selected from one of serum albumin or a fragment thereof, polyethylene glycol, a domain that binds to serum albumin, and a polyethylene glycol-liposome complex; Alternatively, the fragment that improves the target cell binding effect is selected from aptamers or fragments with target binding activity based on antigen-antibody binding effects; Alternatively, the fragment that improves the transmembrane properties of the antimicrobial peptide is a transmembrane peptide selected from TAT, Penetratin, or Arginine-rich peptides.

4. A pharmaceutical composition, characterized in that, The composition includes the antimicrobial peptide of claim 1 or the fusion protein of claim 2, and also includes a pharmaceutically necessary carrier.

5. The pharmaceutical composition according to claim 4, characterized in that, The carrier is selected from at least one of the following: buffer, antioxidant, preservative, bactericide, protein, hydrophilic polymer, amino acid, carbohydrate, chelating agent, tension modifier, surfactant, salt-forming counterion, and metal complex. The buffer is selected from at least one of acetate, Tris, phosphate or citrate; The antioxidant is selected from at least one of ascorbic acid or methionine; The preservative is selected from at least one of octadecyl dimethyl benzyl ammonium chloride, butanol, benzyl alcohol, methylparaben, propylparaben, catechol, resorcinol, cyclohexanol, 3-pentanol or m-cresol; The bactericide is selected from at least one of chlorhexidine diammonium, benzalkonium chloride, or benzyl chloride. The protein is selected from at least one of serum protein, gelatin or immunoglobulin; The hydrophilic polymer is polyvinylpyrrolidone; The amino acid is selected from at least one of glycine, glutamine, asparagine, histidine, arginine, or lysine. The carbohydrate is selected from at least one of glucose, mannose, dextrin, sucrose, mannitol, trehalose or sorbitol; The chelating agent is EDTA; The tension modifier is selected from at least one of trehalose or sodium chloride; The surfactant is polysorbate or TWEE. ® PLURONICS ® Or at least one of polyethylene glycol; The salt-forming counter ion is a sodium ion; The metal complex is a Zn-protein complex.

6. A pharmaceutical preparation for antibacterial purposes, characterized in that, The pharmaceutical formulation comprises the antimicrobial peptide of claim 1, the fusion protein of claim 2 or 3, or the pharmaceutical composition of any one of claims 4-5.

7. The use of the antimicrobial peptide of claim 1, the fusion protein of claim 2 or 3, or the pharmaceutical composition of any one of claims 4-5 in the preparation of an antimicrobial drug; When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.2, the antimicrobial drug is a drug for preventing, improving, or treating diseases related to fungal or bacterial infections; wherein, The fungus is selected from one or more of Candida glabrata and Candida tropicalis; the bacteria is selected from one or more of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.3, the antimicrobial drug is a drug for preventing, improving, or treating diseases related to fungal or bacterial infections; wherein the fungus is pathogenic Candida; the pathogenic Candida is selected from one or more of Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis; the bacteria is selected from one or more of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.4, the antimicrobial drug is a drug for preventing, improving, or treating diseases related to fungal or bacterial infections; wherein the fungus is pathogenic Candida; the pathogenic Candida is selected from one or more of Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis; the bacteria is selected from one or more of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.5, the antimicrobial drug is a drug for preventing, improving, or treating diseases related to fungal or bacterial infections; wherein the fungus is selected from one or more of Candida glabrata, Candida albicans, and Candida tropicalis; and the bacteria is selected from one or more of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.6, the antimicrobial drug is a drug for preventing, improving or treating bacterial infection-related diseases; the bacteria are selected from one or more of Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii.

8. An antifungal composition, characterized in that, The composition comprises the amino acid sequence of the antimicrobial peptide of claim 1 as shown in any one of SEQ ID NO. 2-5 and caspofungin; When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.2, the fungus is selected from one or more of Candida glabrata and Candida tropicalis; When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.3, the fungus is a pathogenic Candida; the pathogenic Candida is selected from one or more of Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.4, the fungus is a pathogenic Candida; the pathogenic Candida is selected from one or more of Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis. When the amino acid sequence of the antimicrobial peptide is as shown in SEQ ID NO.5, the fungus is selected from one or more of Candida glabrata, Candida albicans, and Candida tropicalis.

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