104 results about "C-terminus" patented technology

The invention belongs to the technical field of polypeptide drugs in biochemistry, and discloses three antibacterial peptide analogues as well as a preparation method and application thereof, the sequence of an antibacterial peptide P-1 is CH3CO-GGGENIKKILSKIKLLK-NH2, the sequence of an antibacterial peptide P-2 is CH3CH2CH2CO-GGGENIKKILSKIKLLK-NH2, the sequence of an antibacterial peptide P-3 is CH3 (CH2) 6CO-GGGENIKKILSKIKLLK-NH2, the carboxyl ends of polypeptides are subjected to amidation, and the polypeptides are all positively charged when the pH is equal to 7. The artificially synthesized antibacterial peptide disclosed by the invention shows a remarkable sterilization effect on multidrug resistant staphylococcus epidermidis. P-1, P-2 and P-3 have small molecular weight, are convenient to synthesize, have broad-spectrum bactericidal activity, are self-assembled into nanoparticles, have low cytotoxicity, resist trypsin degradation and the like, and have wide application prospects.

Provided is a polypeptide which contains a polypeptide having at least 80%, 85%, 90%, 95%, or 99% identity to amino acid sequence MTYRPGYNPFG (SEQ ID NO: 41) or amino acid sequence AKGYYRPYGVPV (SEQ ID NO: 22), or a polypeptide having one or more amino acid substitutions, deletions and / or additions relative to the amino acid sequence as shown in SEQ ID NO: 41 or 22. The provided polypeptide can interfere with the binding of a Brag2 synaptic protein to the C terminus of an AMPA receptor, thereby inhibiting NMDA-mediated excessive endocytosis of an AMPA receptor and neuronal apoptosis, and playing a role in protecting neuronal cell activity. Therefore, the polypeptide has application prospects and potential development values as a drug for treating nervous system diseases such as strokes, depression, Alzheimer's disease and drug addiction.

The invention discloses mucosal immune-enhanced recombinant lactobacillus for expressing PEDV (porcine epidemic diarrhea virus) S1 protein as well as a construction method and application of the mucosal immune-enhanced recombinant lactobacillus. The mucosal immune-enhanced recombinant lactobacillus contains a recombinant lactobacillus expression vector for expressing PEDV S1 protein, the amino acid of the PEDV S1 protein is fused with M cell targeting peptide (Co1) and dendritic cell targeting peptide (6aa), the carboxyl terminal of the PEDV S1 protein is fused with a mucosal immune adjuvant (LTB), and the connection sequence of all the parts is Co1-6aa-S1-LTB. According to the mucosal immune enhanced recombinant lactobacillus constructed by the invention, through the synergistic effect of the targeting peptide (DC / MC targeting peptide) and the adjuvant (LTB), the mucosal immune response efficiency (including intestinal mucus SIgA and serum IgG levels) of a PEDV S1 antigen is remarkably improved, humoral immunity, cellular immunity and mucosal immune responses of pregnant animals can be remarkably induced, maternal antibodies are generated, and the immune response efficiency of the pregnant animals is remarkably improved. The intestinal SIgA level of newborn animals is improved, and an effective technical means is provided for prevention and treatment of PED.

The invention discloses decapeptide with antioxidant activity, the amino acid sequence of the decapeptide is amino terminal-APKTLPWGPK-carboxyl terminal, and the decapeptide can be developed into an antioxidant.

The present invention relates to the fields of biomedicine and daily chemicals, and discloses a bioactive peptide having an amino acid sequence of ETRIL, or derivatives thereof having the same biological activity obtained by hydroxylating, carboxylating, carbonylating, methylating, acetylating, phosphorylating, esterifying, or glycosylating the amino acid side chain groups, the amino terminus, or the carboxyl terminus. The bioactive peptide has excellent anti-aging, antioxidant, and sunscreen skin care benefits, is homologous to yeast fermentation products, and can be used in pharmaceuticals, health products, foods, daily chemicals, and other fields, showing promising application prospects.

The application discloses a method for conformational signal peptide-mediated secretion and expression of heterologous proteins in Escherichia coli, and specifically comprises the following steps: simultaneously fusing at least two heterologous proteins to a conformational signal peptide (such as sfGFP) and constructing a heterologous recombinant protein expression vector, wherein the conformational signal peptide has a beta-barrel structure, and the fusion sites are at least two of the amino terminal end, the carboxyl terminal end and a plurality of loop rings of the conformational signal peptide; and then transforming the heterologous recombinant protein expression vector into Escherichia coli and culturing the obtained genetic engineering strain for expression. According to the method, the extracellular secretion and expression of the heterologous proteins in the Escherichia coli can be realized without the mediation of a classical signal peptide, the sfGFP as a fusion tag has no influence on the function of the target protein, and the corresponding target protein can be quickly expressed and purified; and the method expands the secretion and expression path of the protein, can realize the simultaneous expression of a plurality of heterologous proteins, and can effectively improve the expression amount of the target protein.

The invention relates to an anti-mouse IgG nano antibody and alkaline phosphatase fusion protein as well as a preparation method and application thereof. The anti-mouse IgG nano antibody and alkaline phosphatase fusion protein sequentially comprises an anti-mouse IgG nano antibody, a connecting peptide and shewanella alkaline phosphatase from an amino terminal to a carboxyl terminal. The fusion expression of the anti-mouse IgG nano antibody and shewanella alkaline phosphatase in escherichia coli is designed, so that various defects of a chemical labeling method can be avoided, a high-purity and high-specific activity enzyme-labeled antibody can be prepared, the preparation period of a second antibody can be shortened, the preparation process of the second antibody can be simplified, the stability of batches can be improved, and the dependence on experimental animals can be reduced. The prepared anti-mouse IgG nano antibody and alkaline phosphatase fusion protein can be applied to the field of immunodetection, such as a chemiluminescence immunoassay method, an enzyme-linked immunosorbent assay method, an enzymatic fluorescence immunoassay method, an immunoblotting method and the like.

The invention provides a nanopore probe and application thereof, the nanopore probe comprises a polypeptide, the carboxyl terminal of the polypeptide is connected with a steric hindrance tag, the amino terminal of the polypeptide is connected with polyaspartic acid, and the polypeptide has a restriction enzyme cutting site specifically recognized by target protease. The method can prolong the retention time of the polypeptide in the nanopore, enhance the signal discernibility and improve the signal stability, thereby realizing stable and high-precision quantitative detection of the protease activity.

The invention belongs to the field of chemical synthesis, and particularly relates to a chemical synthesis method of elastin-like polypeptide. The invention provides a chemical synthesis method of elastin-like, which comprises the following steps of: constructing a pentapeptide repetitive sequence (valine-proline-glycine-X-glycine, X is amino acid except proline, and the amino acid except glycine is respectively and independently selected from levoamino acid or dextroamino acid) of elastin-like polypeptide through liquid phase reaction; the elastin-like polypeptide can be prepared with the target molecular weight of 1000-500000 by adding amino groups and carboxyl groups into an organic solvent, forming orthogonal protection on the amino groups and the carboxyl groups, then selectively removing amino or carboxyl end protecting groups respectively, accurately coupling the amino groups and the carboxyl groups in a solution and repeating the deprotection and coupling processes for multiple times. The preparation method can realize accurate regulation and control of the molecular weight, sequence, chirality and topological structure of the elastin-like protein, improves the synthesis efficiency of the high-molecular-weight elastin-like polypeptide, has the advantages of large synthesis scale, low cost and the like, and has a wide application prospect.

The present inventors succeeded in improving the antibody constant region to have increased stability under acid conditions, reduced heterogeneity originated from disulfide bonds in the hinge region, reduced heterogeneity originated from the H chain C terminus, and increased stability at high concentrations as well as in discovering novel constant region sequences having reduced Fcγ receptor-binding, while minimizing the generation of novel T-cell epitope peptides. As a result, the present inventors successfully discovered antibody constant regions with improved physicochemical properties (stability and homogeneity), immunogenicity, safety, and pharmacokinetics.

Provided are a polypeptide, a polypeptide-modified magnetic bead, a preparation method therefor, and a use thereof. The C terminus of the polypeptide is modified with cysteine, and the amino acid sequence of the polypeptide is selected from one or more of SEQ ID NOs: 2-4. The polypeptide-modified magnetic bead comprises a magnetic bead, a linker unit, and a polypeptide, wherein the surface of the magnetic bead is modified with hydroxyl; the C terminus of the polypeptide is modified with cysteine, and the amino acid sequence of the polypeptide is selected from one or more of SEQ ID NOs: 1-4; and the end of one side of the linker unit is connected to the surface of the magnetic bead by means of a hydrogen bond, and the end of the other side of the linker unit is connected to the C terminus of the polypeptide by means of a thioether bond. The polypeptide can bind to a specific plasma protein in a targeted manner, especially a low-abundance plasma protein. When the obtained polypeptide-modified magnetic bead is used for plasma protein detection, the binding and detection of the low-abundance protein can be realized without separating high- and low-abundance proteins in plasma. The polypeptide-modified magnetic bead has universality.

The invention discloses a Pichia pastoris indirect surface display system based on a TRAP protein scaffold, which is characterized in that Sed1p protein from saccharomyces cerevisiae is used as anchoring protein, and tetrapeptide repeat affinity protein TRAP is fixed on the anchoring protein on the surface of a Pichia pastoris cell to obtain the Pichia pastoris indirect surface display system based on the TRAP protein scaffold. The target protein with the carboxyl end fused with the peptide MEEVV or the peptide MRRVW is indirectly displayed on the surface of the pichia pastoris cell through specific binding with the tetrapeptide repeat affinity protein TRAP. The xylanase and the beta-xylosidase are indirectly displayed on the surface of the pichia pastoris cell by utilizing the surface display system, so that the pichia pastoris surface display system has the catalytic capabilities of the xylanase and the beta-xylosidase, can perform a synergistic effect to degrade the zelkova xylan, and has a good application prospect.

The present invention discloses a recombinant humanized type XVII collagen, its expression vector and genetically engineered bacteria. In the present invention, 4 functional fragments with high activity are obtained through screening. After optimizing one of the fragments and combining them in a certain order, recombinant humanized type XVII collagen JYC1703 is obtained. Or after optimizing one of the fragments, combining them in a certain order and respectively fusing GPP sequences at the amino terminus and carboxyl terminus, recombinant humanized type XVII collagens JYC1701 and JYC1702 are obtained. After codon optimization, they are amplified and cloned into an expression vector. After enzymatic digestion and linearization, they are transformed into Pichia pastoris competent cells. High-copy recombinants are screened through G418 resistance gradient to obtain Pichia pastoris genetically engineered bacteria expressing recombinant humanized type XVII collagen. The recombinant humanized type XVII collagens JYC1701, JYC1702 and JYC1703 of the present invention exhibit excellent functions of promoting cell adhesion, cell proliferation and migration, and are suitable for preparing products such as skin care or medical devices.

A multi-specific antibody contains at least one binding site for a cell specific antigen and at least one binding site for a tumor-reactive lymphocyte antigen and a multi-specific antibody including an IgG antibody or fragment thereof that binds to a first antigen; and at least one scFv antibody that binds to a second antigen that is different from the first antigen and is linked to a C terminus of at least one light chain or heavy chain of said IgG antibody or fragment. The multi-specific antibody reversibly binds to at least one of the cell specific antigen and tumor-reactive lymphocyte antigen or the first antigen and the second antigen with a greater affinity at an aberrant condition than at a normal physiological condition. Conjugates of the multi-specific antibodies and methods for generating the multi-specific antibody are also provided.

This invention discloses a lipopeptide HIV membrane fusion inhibitor and its pharmaceutical use. The lipopeptide of this invention is of formula I: X1-EMTWEEWEK KVEELEKKIEELLK-X2-X3-X4-X5; or formula II: X1-ELTWEEWEKKVEELEKKIEELLK-X6-X7-X4-X5; wherein, X1 is an amino-terminal protecting group; X2 is a polypeptide sequence (EAAAK)n, A[(EAAAK)n]A, or (EP)n, where n represents the number of repetitions; X3 is Lys, Cys, Dap, Orn, Dab, Dah, or absent; X4 is a lipophilic compound group used to modify the C-terminus; X5 is a carboxyl-terminal protecting group; X6 is a polypeptide sequence KAEEQQKKNE; and X7 is Lys, Cys, Dap, Orn, Dab, or Dah. The lipopeptide of this invention has higher antiviral activity.

The invention provides a whey protein isolate source antioxidant polypeptide, the amino acid sequence of the whey protein isolate source antioxidant polypeptide is amino terminal-LVYPFPGPIP-carboxyl terminal, and the whey protein isolate source antioxidant polypeptide can be developed into an antioxidant.

The present disclosure relates to bispecific binding proteins comprising, from the amino terminal to the carboxy terminal, (a) a first moiety, which is an anti-BAFF antibody or antigen binding fragment thereof, and (b) a second moiety, which is an anti-MASP2scFv or truncated TACI polypeptide. Furthermore, the invention relates to nucleic acid molecules encoding such bispecific binding proteins, as well as vectors and host cells comprising such nucleic acid molecules. The invention further relates to a method for producing said bispecific binding proteins and to the use of said bispecific binding proteins in the treatment of autoimmune diseases.

The present invention discloses an artificial virus receptor and its application, which belongs to the field of biotechnology. The artificial virus receptor of the present invention includes modules A, B, C, D, E, F, G, and H from the amino terminus to the carboxyl terminus. Module A is a signal peptide of type I membrane protein; module B is a customized virus binding domain for capturing target viruses; modules C and E are linkers; module D is a spacer region for forming the skeleton of a customized artificial virus receptor to maintain a certain length outside the cell; module F is a transmembrane domain for realizing cell surface display of the artificial virus receptor; module G is an intracellular domain, which has the function of maintaining the stability of the artificial virus receptor; module H is a tag protein. The present invention paves the way for the rapid construction of in vitro and in vivo infection systems of viruses that are difficult to culture, especially high-risk coronaviruses, and for downstream prospective research, which will help to further advance the life cycle research of many difficult-to-culture viruses and promote the development of antiviral treatments and vaccines.

Disclosed herein, are peptides comprising from N terminus to C terminus, a) a peptide of interest, wherein the peptide of interest having 6 to 20 amino acid residues and a C -terminal residue that facilitates cyclization; b) a G macrocyclase recognition site; c) a linker; and d) G macrocyclase; wherein the peptide is linear, wherein the peptide of interest is covalently bonded to the G macrocyclase recognition site, wherein the G macrocyclase recognition site is bond to the linker, and wherein the linker is bonded to the G macrocyclase, and methods of making cyclized peptides and generating libraries of cyclized peptides.

The present inventors succeeded in improving the antibody constant region to have increased stability under acid conditions, reduced heterogeneity originated from disulfide bonds in the hinge region, reduced heterogeneity originated from the H chain C terminus, and increased stability at high concentrations as well as in discovering novel constant region sequences having reduced Fcγ receptor-binding, while minimizing the generation of novel T-cell epitope peptides. As a result, the present inventors successfully discovered antibody constant regions with improved physicochemical properties (stability and homogeneity), immunogenicity, safety, and pharmacokinetics.

The invention discloses a method for preparing semeglutide by using a natural chemical ligation method, which comprises the following steps: (1) synthesizing semeglutide in two segments, namely an N-terminal segment with carboxyl-terminal hydrazide and a C-terminal segment with amino-terminal cysteine; (2) connecting the two fragments through a natural chemical connection method under a buffer salt condition; and (3) performing desulfurization treatment to convert Cys into target amino acid, and performing purification and freeze-drying after complete treatment. According to the method, the semeglutide is divided into the C-terminal polypeptide fragment and the N-terminal polypeptide fragment, the C-terminal polypeptide fragment and the N-terminal polypeptide fragment are connected through natural chemical connection reaction after being prepared respectively, then desulfurization treatment is conducted, the high-purity and high-yield semeglutide is finally obtained, the problem of difficult sequences is solved, the synthesis efficiency and purity of the semeglutide are remarkably improved, and the method is suitable for industrial production. The method is suitable for large-scale production.

The invention discloses a duck GRPR polypeptide and a preparation method and application of a polyclonal antibody of the duck GRPR polypeptide, and belongs to the field of biochemistry and molecular immunology. The duck GRPR gene is cloned for the first time, and the structure of the duck GRPR gene is analyzed; the preparation method comprises the following steps: taking amino acid polypeptide at 350-368 sites of a carboxyl terminal of duck GRPR protein as a hapten, and carrying out N-terminal modification on a polypeptide sequence to obtain duck GRPR modified polypeptide; and coupling the modified polypeptide with a carrier protein keyhole limpet hemocyanin to prepare a complete antigen, immunizing an animal, and separating and purifying from antiserum to obtain the polyclonal antibody of the duck GRPR polypeptide. Experiments show that the polyclonal antibody can be specifically combined with GRPR protein in duck tissue. According to the invention, the blank in the field of duck GRPR protein detection and research is filled, and a foundation is laid for research of the functions of the GRPR in the duck body.

The invention discloses a whey protein source peptide with hyaluronidase inhibitory activity. The whey protein source peptide is characterized in that the sequence of the whey protein source peptide is amino terminal-GGVSLPEW-carboxyl terminal. The peptide has the advantages of no toxicity, no sensitization and the like, has a remarkable inhibition effect on hyaluronidase, and can be used for developing functional foods or medicines with anti-allergic characteristics.

The invention provides a biosensor for detecting nitrate content as well as a preparation method and application thereof, and relates to the technical field of biology. The biosensor disclosed by the invention comprises a luciferase amino terminal fragment, a luciferase carboxyl terminal fragment and NasR protein, the luciferase amino terminal fragment and the luciferase carboxyl terminal fragment are two fragments of the same luciferase. The biosensor provided by the invention has high selectivity on nitrate, can specifically, stably, continuously and online observe the nitrate content in the whole plant for a long time, and overcomes the key problems of destructive sampling, limited spatial resolution, insufficient detection sensitivity and the like in the traditional method; and a real-time dynamic detection platform capable of monitoring the whole plant living body is provided for plant nitrogen metabolism research.

The application discloses a kind of MS2 virus-like particles based on capsid protein site-directed mutation and its preparation method and application, belong to molecular biological technique field.The amino acid of the beta sheet interface of capsid protein sequence, the amino acid of the interface when two capsid proteins molecules assemble, the carboxyl end site of capsid protein is subjected to site-directed mutation, obtain the mutant that can significantly improve the assembly efficiency and stability of capsid protein dimer.Utilize the mutant to construct MS2 virus-like particles, further by the design of mature enzyme and capsid protein expression element, control mature enzyme weak expression, capsid protein strong expression, to improve assembly efficiency.The application improves the assembly efficiency of MS2 virus by the above strategy, improves the proportion of wrapped RNA, enhances the stability of virus-like particle, greatly prolongs the stable storage time of RNA, improves the purity of wrapped RNA.

The invention discloses a whey protein source peptide with hyaluronidase inhibitory activity. The whey protein source peptide is characterized in that the sequence of the whey protein source peptide is amino terminal-GVSLPEW-carboxyl terminal. The peptide has the advantages of no toxicity, no sensitization and the like, has a remarkable inhibition effect on hyaluronidase, and can be used for developing functional foods or medicines with anti-allergic characteristics.

The application provides an mRNA vaccine and a preparation method and application thereof. Specifically, the application provides application of GMCSF as an immune adjuvant in preparation of an mRNA vaccine, and further provides an mRNA molecule, which encodes a GMCSF-antigen-FC1 fusion protein, wherein the GMCSF-antigen-FC1 fusion protein comprises, from an N terminus to a C terminus, an amino acid sequence of GMCSF, an amino acid sequence of an antigen and an amino acid sequence of FC1 in sequence, wherein the antigen is an antigen from a virus. The mRNA molecule of the application can be used for preparing a vaccine for preventing infection of novel coronavirus BA2 and BA5 mutant strains, and can induce a strong immune response.

The invention relates to a group of scorpion-derived antibacterial peptides capable of destroying cell membranes and application of the scorpion-derived antibacterial peptides. The polypeptides comprise a HeCT1 polypeptide, a HeCT2 polypeptide, a HeCT1-M polypeptide and a HeCT2-M polypeptide, wherein the sequence of the HeCT2 polypeptide is shown as SEQ ID NO.1, the sequence of the HeCT1-M polypeptide is shown as SEQ ID NO.2, and the sequence of the HeCT2-M polypeptide is shown as SEQ ID NO.3, and the sequence of the HeCT2-M polypeptide is shown as SEQ ID NO.4. The carboxyl terminals of the polypeptides are subjected to amidation (-NH2) modification. Furthermore, the polypeptide is an amphiphilic polypeptide, has a cation alpha-helical structure, has the hydrophobicity of 0.4-0.72 and the hydrophobic moment of 0.6-0.9, and has 1-7 net positive charges.

The present disclosure relates to a method for optimizing a virus membrane fusion inhibitor, abroad-spectrum anti-coronavirus lipopeptide and use thereof. The present disclosure provides compounds or pharmaceutically acceptable salts thereof or derivatives thereof, wherein the compounds are shown in formula (I) or formula (II), X1 is an amino-terminal protecting group; X2 is a polypeptide with an amino acid sequence of (EAAAK)n or A[(EAAAK)n]A; X3 is lysine or cysteine or 2,3-diaminopropionic acid or ornithine or 2,4-diaminobutyric acid or 2,7-diaminoheptonic acid; X4 is a lipophilic compound group modified on X3 or X4 is a lipophilic compound group modified on K in X2; X5 is a carboxyl-terminal protecting group.

A tau proteomimetic comprising a cyclic peptide comprising an amino acid sequence NIKHVPGGGSVQIVY (SEQ ID NO: 1) or VPGGGCVQIVYK (SEQ ID NO: 2), such that two amino acids are substituted with cysteine residues, or cysteine residues are positioned at both an amino terminus and a carboxy terminus of the peptide, a linker moiety covalently linking the sulfur atoms of the cysteine residues to form the cyclic peptide, and the N-terminus of the peptide is acetylated and the C-terminus of the peptide is amidated.