9 results about "Histidine residue" patented technology

The invention relates to the technical field of polypeptide compositions, and discloses a silkworm-derived protein peptide with blood sugar regulation and immune function activity and an application method, the silkworm-derived protein peptide comprises a silkworm-derived acidic active peptide group, a silkworm-derived alkaline daemon peptide group, a divalent cation coordination center and a silkworm-derived proline enriched peptide group; the silkworm source acidic active peptide group and the silkworm source alkaline daemon peptide group are mixed according to the mass ratio of (3: 1)-(5: 1), and an electrically neutral nano peptide cluster with the average particle size smaller than 100 nm is formed through electrostatic complexation; the silkworm-derived alkaline daemon peptide group contains histidine residues, imidazolyl of the silkworm-derived alkaline daemon peptide group is protonated in an acid environment to generate charge repulsive force, electrostatic repulsive force generated when active peptide penetrates through intestinal epithelial cell membranes is eliminated by utilizing a component charge counteracting mechanism, the apparent treatment flux of transporter protein on core components is enhanced, and the biological activity of the silkworm-derived alkaline daemon peptide group is improved. And intracellular dissociation of the peptide cluster is triggered by virtue of a protonation induction lock, so that accurate resetting of an active site at a target spot is ensured, and the technical problems that transmembrane absorption of the high-activity polar peptide is limited and intracellular release is delayed are solved.

The invention relates to the field of protein engineering, in particular to a T cell receptor engineering transformation method and application thereof. The T cell receptor engineering transformation method provided by the invention comprises the following steps: obtaining a CDR region of a given T cell receptor sequence through a database, mutating one or more amino acid residues in the CDR region into histidine, and establishing a first T cell receptor mutation library; the T cell receptor engineering transformation method is based on a histidine scanning method, TCR engineering transformation independent of a three-dimensional structure is achieved, the defect of high affinity is overcome, low-affinity and high-activation TCR transformation is achieved, and more choices are provided for clinical application.

The invention relates to a phosphoric acid-enriched cross-linking agent based on photoelectrochemistry and a preparation method and application thereof, and belongs to the technical field of protein structure analysis, the cross-linking agent is 1, 3-bis (2-(1-methyl-3, 5-dioxo-1, 2, 4-triazolidine-4-yl) ethyoxyl) propane-2-yl dihydrogen phosphate, and the cross-linking agent is 1, 3-bis (2-(1-methyl-3, 5-dioxo-1, 2, 4-triazolidine-4-yl) ethyoxyl) propane-2-yl dihydrogen phosphate. Two identical reaction groups, namely a methylurazole group and a phosphate group are used as affinity enrichment tags; the preparation method comprises synthesis of a methylurazole precursor, synthesis of an OMs precursor, synthesis of a compound 2 and the like. Tyrosine and histidine residues can be selectively targeted with the cross-linking agent through a controllable electrochemical click reaction and a photocatalytic reaction. The synthesis steps are simple, the raw materials are easy to obtain, the price is low, environment friendliness is achieved, the crosslinking reaction can be completed under the condition close to the physiological condition (pH 7.4), the prepared stable and water-soluble connecting agent has an innovative modular framework and acts on multiple amino acids (such as tyrosine and histidine), and the result shows that accurate and rich information is provided for pBMT-based connection, and the application prospect is wide. The protein structure analysis is facilitated.

The invention discloses a high-enzyme-loading-amount liver targeted drug delivery system based on gradient biomimetic mineralization as well as a preparation method and application of the high-enzyme-loading-amount liver targeted drug delivery system. According to the system, protein serves as a nucleation site, zinc ions and a 2-methylimidazole framework are gradually assembled in a mild water phase environment by utilizing the coordination effect of histidine residues and metal ions in a protein structure, a protein-metal organic framework compound (Pmof) with high drug loading capacity is constructed, and small molecule drugs can be loaded at the same time. The delivery system has a remarkable liver targeting capability, can be efficiently enriched in liver tissues, and synchronously releases protein drugs and small molecule drugs. The problem that an existing carrier is low in enzyme loading amount is solved, the preparation process is mild, biocompatibility is good, and the carrier can be used for developing other drugs for treating liver diseases and has remarkable clinical transformation prospects.

Genetically modified non-human animals are provided that express an immunoglobulin variable domain that comprises at least one histidine, wherein the at least one histidine is encoded by a substitution of a non-histidine codon in the germline of the animal with a histidine codon, or the insertion of a histidine codon in a germline immunoglobulin nucleic acid sequence. Immunoglobulin genes comprising histidines in one or more CDRs, in an N-terminal region, and / or in a loop 4 region are also provided. Immunoglobulin variable domains comprising one or more histidines (e.g., histidine clusters) substituted for non-antigen-binding non-histidine residues. Non-human animals that are progeny of animals comprising modified heavy chain variable loci (V, D, J segments), modified light chain variable loci (V, J segments), and rearranged germline light chain genes (VJ sequences) are also provided. Non-human animals that make immunoglobulin domains that bind antigens in a pH-sensitive manner are provided.

This invention relates to the field of biopharmaceutical manufacturing technology and discloses a specific antibody against HER2 and its application, comprising: a heavy chain and a light chain variable region, wherein the complementarity-determining region contains a pH-sensitive binding region composed of histidine residues and hydrophobic residue clusters, and the hydrophobic residue clusters are located in the vicinity of the imidazole ring side chain of the histidine residues, in order to establish a desolvation shielding microenvironment with a low dielectric constant. This invention utilizes the physical shielding of the microenvironment against the solvation interference of water molecules in the blood to maintain the electroneutrality of histidine residues in the physiological environment to stabilize the binding affinity, and in the acidic environment, responds to the proton flow to generate charge flipping and hydration volume expansion stress, synergistically driving the antibody to dissociate from the receptor, thereby solving the drug resistance problem caused by target circulation escape, and improving the efficiency of intracellular receptor downregulation while ensuring serum stability.

The present invention aims to provide a fucose-binding protein that shows improved productivity in cases of expression in a host such as Escherichia coli, improved binding affinity to a fucose-containing sugar chain such as a sugar chain containing a structure composed of Fucα1-2Galβ1-3GlcNAc and / or Fucα1-2Galβ1-3GalNAc, and / or improved thermal stability. The above object is achieved by deleting a plurality of amino acid residues in the C-terminal side of the amino acid sequence of the fucose-binding protein BC2LCN of SEQ ID NO: 1, and, when necessary, substituting the glycine residue at position 36 in SEQ ID NO: 1 with a cysteine residue, substituting the glutamine residue at position 39 in SEQ ID NO: 1 with a leucine residue or methionine residue, substituting the glutamine residue at position 65 in SEQ ID NO: 1 with a leucine residue, substituting the cysteine residue at position 72 in SEQ ID NO: 1 with a glycine residue or alanine residue, substituting the glutamic acid residue at position 81 in SEQ ID NO: 1 with a cysteine residue, glutamine residue, histidine residue, or methionine residue, and / or substituting the glycine residue identified as the residue at position 36 in SEQ ID NO: 1 with a cysteine residue.

The subject of this invention is a construct of an expression vector for expressing recombinant µ-conotoxin TIIIA or TIIIAlaMut, characterized in that it comprises the nucleotide sequence of µ-conotoxin TIIIA SEQ ID NO:1 or the nucleotide sequence of µ-conotoxin TIIIAlaMut SEQ ID NO:4, both sequences containing a sequence encoding six histidine residues (6His) at the 5' end, which is linked via a serine-glycine-serine linker (SGS) to a construct encoding a TRX::TIIIA fusion protein or a TRX::TIIIAlaMut fusion protein, wherein the TRX::TIIIA fusion protein comprises the µ-conotoxin TIIIA gene and a gene encoding a leader protein, and the TRX::TIIIAlaMut fusion protein comprises the µ-conotoxin TIIIAlaMut gene and a leader protein, wherein the leader protein is a thioredoxin (TRX) modified by site-directed mutagenesis, wherein the amino acid methionine at position 37 is replaced by lysine. Another subject of the invention is an expression vector comprising a construct according to the invention under the control of a constitutive promoter. Another subject of the invention is isolated *E. coli* cells comprising an expression vector according to the invention. Another subject of the invention is a method for producing µ-conotoxin TIIIA or TIIIAlaMut in *E. coli* using an expression vector comprising a construct according to the invention, characterized in that the method comprises the steps of: a) transforming *E. coli* cells with an expression vector comprising a construct according to the invention under the control of a constitutive promoter, said expression vector encoding a TRX::TIIIA fusion protein having the amino acid sequence SEQ ID NO:2 or having SEQ ID NO:2. a) TRX::TIIIAlaMut fusion protein NO:5; b) Expression of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein; c) Isolation and purification of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein; d) Formation of disulfide bonds by glutathione treatment of the purified TRX::TIIIA or TRX::TIIIAlaMut fusion protein in GSH / GSSG and dialyzing in buffer; e) Cleavage of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein with the formed disulfide bonds by cyanogen bromide; f) Purification of the cleaved TIIIA or TIIIAlaMut peptide.

The present invention provides a peptide having specificity or selectivity of binding to human IgG. The peptide is characterized by comprising an amino acid sequence consisting of 13 to 17 amino acid residues represented by Formula I, and is capable of binding to human IgG: (X 1-3 )-C-(X2)-H-R-G-(Xaa1)-L-V-W-C-(X 1-3 ), wherein X is independently any amino acid residue other than cysteine, C is a cysteine residue, H is a histidine residue, R is an arginine residue, G is a glycine residue, Xaa1 is a glutamic acid residue or an asparagine residue, L is a leucine residue, V is a valine residue, and W is a tryptophan residue.