33 results about "Disulphide bond formation" patented technology

An expression system which provides heterologous proteins expressed by a non-native host organism but which have native-protein-like biological activity and/or structure. Disclosed are vectors, expression hosts and methods for expressing the heterologous proteins. The expression system involves co-expression of protein factor(s) which is/are capable of catalyzing disulphide bond formation and desired heterologous protein(s). The expression system is presented using yeast cells as the preferred host, protein disulphide isomerase (PDI) and thioredoxin (TRX) as the preferred examples of the protein factors and HCV-E2715 envelope glycoprotein and human FIGF as the preferred examples of the heterologous proteins.

The invention belongs to the field of polypeptide synthesis, and relates to a solid-phase synthesis method of ziconotide by a segment process. The method aims to solve the technical problems of long synthesis period and low crude peptide purity in the existing preparation method, and the technical problems of complex operation, low total yield and the like in the disulfide-bond formation process. The technical scheme is as follows: the method comprises the following steps: synthesizing four segment peptides [19-25]A, [12-18]B, [6-11]C and [1-5]D of ziconotide by a solid-phase process; sequentially connecting the all-protected peptide fragments B, C and D to the peptide resin A, and cracking to obtain a ziconotide linear peptide; and finally, carrying out liquid-phase one-step oxidization, which has the advantages of mild conditions, simplified operation, easy after-treatment and environment friendliness, to obtain the ziconotide. The technical scheme can greatly shorten the synthesis period, lower the synthesis and purification difficulty and the production cost, and enhance the purity of the linear peptide and the total yield of the product. The method is beneficial to industrial large-scale production.

Elimination of disulphide bond formation of cysteine-containing S. aureus antigens enhances antigen stability. The invention provides variant forms of cysteine-containing S. aureus antigen with a point mutation that replaces, deletes or modifies the cysteine residue.

The plasmid for efficiently expressing the polypeptide toxin provided by the invention is obtained by cloning a coding gene of the polypeptide toxin into a plasmid vector pET-26b-DsbC, the plasmid vector pET-26b-DsbC carries His, pelB/ompT and a DsbC tag, the DsbC tag and a pelB/ompT signal peptide jointly act, polypeptide to be expressed is transferred into periplasm which is more beneficial to protein folding and disulfide bond formation, and the expression efficiency of the polypeptide toxin is improved. The soluble expression of the polypeptide toxin is improved, the problem of no expression or low expression quantity of the polypeptide toxin is solved, and the high-yield expression of the polypeptide toxin is realized. The invention further provides a preparation method of the plasmid, the plasmid for expressing the spider toxin is prepared, then the gene engineering bacteria are used for culturing and expressing the spider toxin, the prepared spider toxin is high in yield and low in production cost, and the preparation method has huge application prospects in the field of polypeptide toxin production.

The invention discloses a method for extracting edible rice starch and rice protein from broken rice with excessive pesticide residues. According to the method, pesticide residues such as isoprothiolane and hexaconazole and mycotoxins such as aflatoxin are oxidized and degraded into non-toxic substances through oxidizing agents such as sodium hypochlorite, chlorine dioxide and hydrogen peroxide, disulfide bonds of protein are opened at the same time, stable sulfonic acid groups with high solubility are formed, protein dissolution is increased, the yield is increased, residual protein in starch is reduced, and protein and starch products with better safety are obtained.

Methods and prokaryotic expression systems for producing recombinant disulfide bond-containing proteins are described including increasing the level of at least one redox cofactor in the cell to enhance disulfide bond formation are disclosed. Processes of increasing levels of redox cofactors include media supplementation and genetic modification of the host cell. The process can yield increased levels of soluble or active protein, or can assist the proper processing of recombinant proteins in expression systems.

The invention provides application of a molecular allosteric body and dimer of a human growth hormone releasing hormone (hGHRH) similar peptide in treating GH deficiency, infertility, senile dementiaand diabetes and enhancing immunity. The dimer is formed by connecting two identical hGHRH similar peptide monomers containing a single cysteine molecule allosteric structure through a disulfide bondformed by cysteine, and an H-shaped structure (intramolecular single Ser-to-Cys substitution) is formed. A side chain epsilon-amino of one lysine of the GHRH similar peptide is also subjected to fattyacid chain modification. Through fatty acid modification, the GH sustained release time of the GHRH similar peptide monomer or dimer is prolonged in vivo, and the longest release time reaches 17 days. The invention finds that the GHRH dimer with long-acting activity has an Aib-to-2Ala substitution structure, an 18C-to-18C disulfide bond formation structure, a C20 fatty acid chain modification structure and a C-terminal amidation structure.

Elimination of disulphide bond formation of cysteine-containing S.aureus antigens enhances antigen stability. The invention provides a composition comprising variant forms of cysteine-containing S.aureus antigen with a point mutation that replaces, deletes or modifies the cysteine residue.

Elimination of disulphide bond formation of cysteine-containing S. aureus antigens enhances antigen stability. The invention provides variant forms of cysteine-containing S. aureus antigen with a point mutation that replaces, deletes or modifies the cysteine residue.

The present invention relates generally to the field of immunomodulation. Taught herein is an agent for inhibiting immunostimulation mediated by a Toll-like receptor useful in the treatment of viral and microbial pathogenesis, diseases involving elements of autoimmunity and inflammation as well as cancer. The agent antagonizes disulfide bond formation between C98 and C475 of Toll-like receptor 7 (TLR7) thereby preventing TLR7 activation.Pharmaceutical compositions are also enabled herein.

Disclosed are an anti-bFGF humanized double-stranded antibody with stable disulfide bond, the preparation method and the applications thereof. The amino acid sequence of the anti-bFGF humanized ds-Diabody is shown in SEQ ID NO. 1. The nucleotide sequence of gene encoding the anti-bFGF humanized ds-Diabody is shown in SEQ ID NO. 2. By site-directed mutation, two cysteine residues are introduced into each single-stranded antibody, thus introducing the disulfide bond and form ds-Diabody. It is shown by experiments that the obtained ds-Diabody has the following advantages: enhanced stability; better affinity when binding to the specific antigen bFGF; moderate relative molecular weight, good tumor targeting, more powerful in tumor tissue penetration, and higher blood clearance rate, showing a broad application prospects in the clinic diagnosis and tumor therapy.

The invention discloses a preparation method of a beta-defensin 2 antibacterial peptide. The preparation method comprises the following steps: S1, selecting Fmoc-Pro-2-Chloro-Resin resin, carrying out swelling, and then removing an Fmoc protecting group; and S2, according to the sequence of the beta-defensin 2 antibacterial peptide, sequentially carrying out coupling from the C terminal to the N terminal until the last amino acid Fmoc-Gly-OH, and removing the Fmoc protecting group to obtain the beta-defensin 2 antibacterial peptide resin peptide. According to the preparation method, an Fmoc solid phase method is used, short dipeptide and short tripeptide are selected as reaction raw materials for coupling, generation of impurities is reduced, the idea that a pair of disulfide bonds is formed through oxidation to form a relatively stable structure, and then the remaining two pairs of disulfide bonds are formed through natural oxidation is adopted, so that the purposes of high purity and high yield of a crude product are achieved; the method has the advantages of high operability and reduction of emission of three wastes, can be used for large-scale production, has high theoretical guidance value and considerable economic and practical value, and is wide in application prospect.

The invention features homo-multimers, e.g., homo-trimers, of TNFSF or TNF-like ligand muteins in which each TNFSF ligand or TNF-like ligand mutein monomer contains at least one cysteine residue substitution or insertion that promotes the formation of a disulfide bond with a cysteine residue on a neighboring TNFSF or TNF-like ligand mutein monomer. The invention features methods of producing such TNFSF and TNF-like ligand muteins, pharmaceutical compositions containing such muteins, and methods of using such muteins in cancer immunotherapy, in treating autoimmune and neurological diseases, and in reducing or eliminating the complications and risks of rejection in organ transplantation or tissue or organ repair or regeneration.

The invention relates to an amphotericin B albumin nanometer preparation and a preparation method and application thereof. Under the action of heating, a reducing agent and a surfactant, a hydrophobicregion and intramolecular disulfide bonds of proteins are destroyed, albumin molecules rich in free sulfhydryl are formed; through an intermolecular disulfide bond network and hydrophobic interaction, albumin nanometer particles are formed; in the process of forming the intermolecular disulfide bond network, micromolecule antibacterials amphotericin B is introduced, and the amphotericin B albuminnanometer preparation can be formed. Compared with the prior art, high binding force between amphotericin B and albumin is sufficiently used, defects existing in the prior art are converted into advantages, and the amphotericin B albumin nanometer preparation hopefully exerts great application potentials in anti-infective therapy. In vitro and in vivo experiments indicate that the nanometer system changes biological distribution of the amphotericin B, and accumulation of medicines in kidneys is reduced.

The invention belongs to the technical field of antibacterial agents, and particularly relates to a cyclic polypeptide for preventing candida albicans and a preparation method of the cyclic polypeptide. The amino acid sequence of the cyclic polypeptide is represented by SEQ ID NO. 1, and the cyclic polypeptide is an intramolecular cyclic polypeptide; an intramolecular disulfide bond is formed between two cysteine residues in the amino acid sequence of the cyclic polypeptide, and accordingly, an intramolecular cyclic structure is formed; the tail of a terminal C is composed of eight arginines,the sequence has two unnatural amino acids, and proline located at the beta-turn of the polypeptide is replaced by DPRO-LPRO to improve the stability of the beta-turn. The cyclic polypeptide has a simple amino acid sequence structure, is convenient to synthesize, is used for preventing and treating diseases caused by the candida albicans, and has high antibacterial activity.

This invention pertains to the design and synthesis of molecules that can act as protein mimics. In particular this disclosure teaches the preparation of short, cyclic peptide sequences that can adopt a helical conformation and display a particular arrangement of amino acid side chains oriented in a specific arrangement to serve as a pharmacophore. A ring, formed by a disulfide bridge between pairs of cysteine residues, maintains the helical structure. When the cysteines are arranged in a pattern of i to i+3 as illustrated in FIG. 1, and when the first cysteine is of the D-configuration, and the second cysteine is of the L-configuration, the helical arrangement is especially stabilized. A preferred version of this invention involves a pentapeptide sequence of general structure known as the NR Box, stabilized by a side chain to side chain disulfide bridge formed from the two cysteines.