159 results about "Amino acid mutation" patented technology

Disclosed herein are predictive models for T-cell epitope prediction, B-cell epitope prediction, and protein design wherein a method is implemented for generating a protein variant amino acid sequence of a target protein having one or more modified properties, the method comprising: (a) iteratively sampling an input amino acid sequence of the target protein, and (b) sampling the individual protein score of at least one weighted relative contribution of the single residue mutant input amino acid sequence to the at least one target property across a plurality of other single residue mutant input amino acid sequences to generate a combined protein score, wherein the combined protein score corresponds to the protein variant comprising one or more amino acid mutations of the single residue mutant input amino acid sequences.

A varicella-zoster virus (VZV) nanoparticle protein, and a preparation method therefor and a use thereof. The VZV protein comprises a partial or full sequence of an amino acid sequence of an extracellular region of a VZV gE glycoprotein, with W at position 200 mutation to C and L at position 245 mutation to C in the amino acid sequence of the extracellular region of the VZV gE glycoprotein. By means of the rational optimization design of the amino acid sequence of the VZV gE protein by means of protein genetic engineering, the VZV gE recombinant protein modified with amino acid mutations has increased stability and immunogenicity compared with the VZV gE protein. Moreover, by further designing the protein structure, the VZV gE protein is repeatedly displayed on the surface of ferritin nanoparticles with the desired epitopes exposed, thereby further enhancing immunogenicity.

This invention belongs to the field of enzyme engineering technology and discloses a BhrPETase mutant and its applications. The invention provides a BhrPETase mutant with the amino acid sequence shown in SEQ ID No. 2, designated as mutant F208I. Compared to the wild-type mutant BhrPETase, this mutant exhibits a 1.39-fold increase in PET degradation activity. Based on mutant F208I, this invention further rationally designs amino acid mutations, providing 21 BhrPETase mutants. The BhrPETase mutants provided by this invention, while maintaining thermal stability essentially equivalent to wild-type BhrPETase, increase PET degradation activity by 1.39 to 4.24 times. The BhrPETase mutants provided by this invention can be applied in fields such as PET degradation, PET degradation product recovery, or the preparation of PET degradation agents.

The invention provides a method for preparing (R)-4-chloro-3-hydroxybutyric acid ethyl ester ((R)-CHBE) through enzyme catalysis, which comprises the following steps: isopropanol is used as a hydrogen donor, a ketoreductase mutant is used for carrying out catalytic reduction reaction of COBE to prepare (R)-CHBE, and the ketoreductase mutant has amino acid mutation at the 83rd site on the basis of an amino acid sequence shown as SEQ ID NO.1. The invention also provides a preparation method of (R)-4-chloro-3-hydroxybutyric acid ethyl ester ((R)-CHBE). The thermal stability, namely heat resistance, of the ketoreductase mutant is improved, and by combining with the use of a rectifying tower, the method disclosed by the invention improves the utilization rate of isopropanol and can discharge a byproduct acetone in time, so that the substrate conversion rate and the product concentration are improved. The invention also provides an enzyme catalysis device used in the method.

The invention discloses a milk-derived broad-spectrum antibacterial peptide W-2 and application thereof, and relates to the technical field of biology. The amino acid sequence of the antibacterial peptide is as shown in SEQ ID NO. 4. Symmetrical structure design and amino acid mutation are carried out on the basis of the template peptide to obtain the novel antibacterial peptide, and tests show that the novel antibacterial peptide has broad-spectrum antibacterial activity which is obviously higher than that of the template peptide, and basically has no cytotoxicity. The antibacterial peptide prepared by the invention still keeps good antibacterial activity in physiological salt concentration and protease environment, has certain serum stability, and has higher application value; in addition, the antibacterial peptide has a good inhibition effect on the formation of a bacterial biofilm, and has a synergistic effect with traditional antibiotics.

The invention provides a hyoscyamine 6 beta hydroxylase mutant as well as a preparation method and application thereof. The hyoscyamine 6 beta hydroxylase mutant at least has the following two sites or amino acid mutation in functional equivalent sites compared with wild hyoscyamine 6 beta hydroxylase: the 14th site and the 97th site; the wild type hyoscyamine 6 beta hydroxylase has an amino acid sequence as shown in SEQ ID NO: 1. The obtained hyoscyamine 6 beta hydroxylase mutant has higher hydroxylation activity, and meanwhile, the epoxidation capacity disappears or is reduced. In industrial application, the catalytic efficiency can be remarkably improved, reagent waste is reduced, the production cost is saved, generation of redundant by-products in chemical reaction is reduced, and environmental pollution is reduced.

The invention relates to the field of biochemical engineering, in particular to an alcohol dehydrogenase mutant and application thereof. The mutant is obtained by carrying out mutation on one or more sites selected from 111Y, 258V, 283L, 274L, 107K and 108N aiming at alcohol dehydrogenase, and the mutation is that amino acid at the sites is mutated into one of W, Q, V, G and A. The enzyme activity of the alcohol dehydrogenase mutant is higher than that of a wild type; the enzyme specific activity (36.42) of the mutant A-111-107-274 taking FAL as a substrate is 2.4 times that of a wild type, and the enzyme specific activity (22.16) of the mutant A-111-107-274 taking HMF as a substrate is 9.2 times that of the wild type. Good industrial application performance is shown.

The invention provides a DNA polymerase mutant and application thereof. Compared with a wild type KOD DNA polymerase, the DNA polymerase mutant has amino acid mutation at the 408th site, the 409th site or a functional equivalent site; and an amino acid mutation of at least one site selected from the following 23 sites and functional equivalence sites: 141 site, 143 site, 147 site, 383 site, 384 site, 389 site, 485 site, 584 site, 589 site, 397 site, 424 site, 432 site, 445 site, 523 site, 553 site, 561 site, 564 site, 461 site, 481 site, 605 site, 663 site, 711 site, and 725 site; the amino acid sequence except the amino acid mutation site of the mutant has at least 90% identity with the corresponding amino acid sequence of the wild type KODDNA polymerase; the wild type KOD DNA polymerase has an amino acid sequence as shown in SEQ ID NO: 2.

The present invention provides a carbonyl reductase mutant, preparation method and use thereof, and a preparation method of ethyl (R)-6-hydroxy-8-chlorooctanoate. The carbonyl reductase mutant is a carbonyl reductase with amino acid mutation; the carbonyl reductase comprises an amino acid sequence as set forth in SEQ ID NO: 2; the amino acid mutation includes E101V, F214R or E101V / F214R. In the present invention, by introducing mutations on the basis of the original carbonyl reductase sequence, the enzyme activity is improved, the stereoselectivity is improved, and ethyl (R)-6-hydroxy-8-chlorooctanoate can be obtained with high yield and high purity under relatively mild conditions, which reduces the production cost and is suitable for industrial production.

The invention relates to the technical field of enzyme engineering, in particular to a xylose reductase XR21 mutant and application thereof. Specifically, the invention provides a novel xylose reductase mutant aiming at the defect of poorer thermal stability of the existing wild type xylose reductase, and particularly provides a xylose reductase mutant which is obtained by performing single or multiple site amino acid mutation on the 19th site, the 48th site, the 79th site, the 208th site and the 300th site of a xylose reductase sequence shown as SEQ ID NO: 2, compared with wild type xylose reductase, the obtained xylose reductase mutant has the advantages that the activity of catalyzing an epimer substrate arabinose into arabitol can be obviously reduced, and meanwhile, the selectivity to xylose is improved, so that the operation process of downstream separation and purification is simplified, and the biological catalysis requirement of green industry is met.

The invention discloses a double-function (p) ppGpp synthetase or hydrolase mutant, a biological material and application of the double-function (p) ppGpp synthetase or hydrolase mutant to preparation of L-threonine, and belongs to the technical field of gene engineering. The technical problem to be solved by the invention is how to improve the yield of L-threonine. Relative to a wild type, the bifunctional (p) ppGpp synthetase or hydrolase mutant comprises one or more of the following mutations: K1) mutation of 174th amino acid of SEQ ID NO: 2 into cysteine, K2) mutation of 529th amino acid of SEQ ID NO: 2 into phenylalanine, and K3) insertion of histidine and aspartic acid between 84th amino acid and 85th amino acid of SEQ ID NO: 2. The bifunctional (p) ppGpp synthetase or hydrolase mutant provided by the invention can be used for improving the yield of L-threonine of Escherichia coli.

The application discloses a key type specificity changed alpha-glucosyltransferase mutant, and belongs to the technical field of enzyme engineering and starch modification. The method is characterized in that, by analyzing the combination of Lf2970GtfB 4,3-alpha-glucosyltransferase in the active center donor / acceptor sub-site and the substrate, part of key amino acids of Lf2970GtfB are mutated into different types of amino acids, the mutant is prepared by changing the enzyme and substrate interaction force, space steric hindrance and other factors affecting the orientation of the substrate in the active center, the transglycosylation is changed, and the bond type composition of the product is changed. The application changes the bond type specificity of Lf2970GtfB 4,3-alpha-glucosyltransferase by mutation, the obtained mutant has novel 4,3 / 6-alpha-glucosyltransferase activity, and is helpful to synthesizing unique structure and more valuable alpha-glucan by using starch substrates.

The application discloses a D type influenza virus isolate D / HY11 and application thereof in a mink infection model, and belongs to the field of biological medicines. The application takes the D type influenza virus isolate D / HY11 of an IDV northeast isolate as a research object, establishes a mink transmission model, evaluates the transmission dynamics characteristics of the strain among minks, identifies amino acid mutations possibly related to host adaptability through whole genome sequencing, analyzes the amino acid substitution on receptor affinity based on computer simulation of protein conformation and receptor molecule docking, explores the host adaptation evolution law of the virus in the transmission process, and provides an important scientific basis for early warning and prevention and control of a public health crisis possibly caused by the IDV.

The application provides a glutaminase mutant and application thereof. The glutaminase mutant comprises: (a) a protein which is subjected to amino acid mutation at at least one of the following positions: S467, Y334, K400, N521, R337, E402 or D447 of the amino acid sequence shown in SEQ ID NO: 2 and has a glutaminase activity function; and (b) a protein which has more than 80% homology with the amino acid sequence defined in (a) and has a glutaminase function. The glutaminase mutant with the amino acid sequence of the application has high specific enzyme activity when performing enzyme catalysis, is low in cost when used for commercial food processing, and is strong in market competitiveness.

This invention provides an imine reductase mutant, its preparation method, and its application in the catalytic preparation of dextromethorphan intermediates. The imine reductase mutant is an imine reductase with an amino acid mutation, comprising the amino acid sequence shown in SEQ ID NO:1. The amino acid mutation type includes any one or a combination of at least two of I122T, D212A, or G228R. By introducing a mutation into the imine reductase, this invention significantly improves the enzyme's activity and stereoselectivity, enabling the high-yield synthesis of the dextromethorphan intermediate (S)-1-(4-methoxybenzyl)-1,2,3,4,5,6,7,8-octahydroisoquinoline under mild conditions, greatly reducing production costs and making it suitable for industrial production.

The invention belongs to the technical field of biological medicine, and particularly relates to a PDHC mutant, an immunogenic fragment and application, the PDHC mutant has amino acid mutation at at least one of the 214th site, the 274th site or the 294th site of the amino acid sequence shown in SEQ ID NO: 1, and the PDHC mutant is used for preventing or treating staphylococcus aureus (SA) infection and is an mRNA vaccine for preventing or treating staphylococcus aureus (SA) infection. The stability and immunogenicity of the staphylococcus aureus PDHC antigen are greatly improved, efficient targeted delivery of the antigen is achieved, and the immune effect of the vaccine is remarkably improved.

The invention relates to the technical field of enzyme engineering, in particular to a xylose reductase XR31 mutant and application thereof. Specifically, the invention provides a novel xylose reductase mutant aiming at the defect of poor thermal stability of the existing wild type xylose reductase (SEQ ID NO: 2), and particularly provides a xylose reductase mutant which is obtained by performing single or multiple site amino acid mutation on the 21st site, the 46th site, the 128th site, the 168th site and the 205th site of a xylose reductase sequence shown as SEQ ID NO: 2, compared with wild type xylose reductase, the obtained xylose reductase mutant has the advantages that the catalytic activity and the thermal stability on substrate xylose are obviously improved, the xylose reductase mutant can stably work under a high-temperature condition, and substrate conversion in industrial application is more efficiently realized.

The invention discloses a polyphosphate kinase mutant, a coding gene and application of the polyphosphate kinase mutant, and belongs to the technical field of bioengineering. The polyphosphate kinase mutant disclosed by the invention is obtained by carrying out amino acid mutation on PPK2 from Sphingobium siyangense 1.6855, wherein the amino acid sequence of the PPK2 is as shown in SEQ ID NO.1, and the site of the amino acid mutation is at least one of I125F, I192P and S228A. The PPK2 mutant disclosed by the invention has excellent thermal stability, and the enzymatic activity retention rate of the mutant after thermal treatment can be up to 20 times or more that of a wild type. The PPK2 mutant can efficiently catalyze ADP (adenosine diphosphate) to generate ATP (adenosine triphosphate), the product yield is high, no by-product is generated, and the PPK2 mutant has a good industrial application prospect.

Provided in the present invention are a glucose dehydrogenase mutant and use thereof. The glucose dehydrogenase mutant comprises: (a) a protein having an amino acid sequence shown in SEQ ID NO: 1; or (b) a protein that has been subjected to amino acid mutation at at least one of the following sites of the amino acid sequence in (a): E96, A47, V72, K137, V11, V88, V140, I183, A100, D202, D255, or Q170, and has a glucose dehydrogenase activity function; and (c) a protein having at least 80% homology with the amino acid sequence defined in any one of (a) and (b) and having a glucose dehydrogenase function. The glucose dehydrogenase mutant of the present application has better tolerance and higher activity under extreme conditions, is suitable for industrial scale-up, and has low cost and high yield.

The application discloses a base editor ACGBEmax realizing simultaneous replacement of purine and pyrimidine, relates to the technical field of gene editing, and comprises, from N end to C end, an HMCES protein, a bifunctional deaminase TadDual, an nCas9(D10A) protein and an engineered N-methyl purine DNA glycosylase eMPG. The base editor can realize simultaneous replacement of purine and pyrimidine, significantly increases the diversity of mutants after targeted editing, has the advantages of high editing efficiency and low Indels rate, and has great application value in aspects of in vitro and in vivo protein mutation screening and identification of oncogenic amino acid mutations.

Provided in the present application are a glycosylated fusion protein, a nucleic acid molecule, an expression vector, a host cell and the use thereof. A first aspect of the present application provides the glycosylated fusion protein, comprising a murine Fc variant and a hepatitis B virus antigen, wherein the murine Fc variant is obtained by performing amino acid mutation and non-mammalian glycosylation modification on a murine Fc fragment, the murine Fc variant comprises at least one of alanine at position 223, alanine at position 228, alanine at position 230, leucine at position 330, and glutamic acid at position 332, the glycosylation modification does not comprise sialic acid modification, and the positions are numbered according to the EU numbering system. The fusion protein can bind to DC cells and activate DC cells, and thus promote the proliferation and activation of specific T cells.

To provide a modified mycoplasma protein M.SOLUTION: Provided is a modified Mycoplasma protein M or a functional fragment thereof, wherein the modified Mycoplasma protein M or a functional fragment thereof has one or more amino acid mutations that increase or maintain the thermostability of the Mycoplasma protein M or a functional fragment thereof as compared to a wild-type Mycoplasma protein M or a functional fragment thereof.SELECTED DRAWING: Figure 1

The invention relates to the technical field of gene engineering, in particular to a lipase mutant, a coding gene, a recombinant vector, engineering bacteria and application. According to the lipase mutant, amino acid V at the 142 site of lipase Lip with the amino acid sequence shown as SEQ ID No.1 is mutated into I, amino acid N at the 169 site of the lipase Lip is mutated into D, amino acid K at the 212 site of the lipase Lip is mutated into E, and the amino acid sequence of the lipase mutant is shown as SEQ ID No.2. The lipase activity induced by the engineering bacterium pPICZ alpha A-lip / X33 of the mutant gene obtained by the invention is 6923 U / mL under the condition that the pH value is 9.0, and is 7.1 times that of the original gene engineering bacterium; the residual enzyme activity of the mutant lipase is 90% and is far higher than the residual enzyme activity of the original lipase under the same treatment condition when the temperature is kept at 70 DEG C for 1 h. The mutant enzyme has the characteristics of high temperature resistance and high enzyme activity under an alkaline condition, which indicates that the mutant enzyme has important application prospects in the industries of cotton and linen processing, leather degreasing, sewage treatment and the like.

The invention belongs to the technical field of biological enzymes, and discloses a cytochrome P450 enzyme mutant and application thereof, the mutant is subjected to any one of the following amino acid mutations on an amino acid sequence as shown in SEQ ID NO.2: L294A, L294G, L294A + T89H and L294G + T89H. The cytochrome P450 enzyme mutant provided by the invention can selectively catalyze a 7beta hydroxylation reaction of a steroid compound to generate a corresponding 7beta-hydroxylated steroid compound (such as UDCA, CA and the like), and has excellent selectivity (-96%) and / or relatively high yield (-70%), the catalytic reaction efficiency is high, and the reaction time can be shortened to be within 20 hours.

This invention proposes a method for screening bisphenol A-specific peptides using molecular simulation, belonging to the field of food safety technology. The method includes the following steps: 1) Through protein stacking and molecular docking, the molecular structure and interactions of bisphenol A-protein cocrystal compounds in a protein structure database are comprehensively analyzed to obtain the receptor protein and the original parent chain; 2) Based on the original parent chain obtained in step 1), the parent peptide is obtained by truncation of the parent peptide segment by analyzing the main active amino acids in the molecular docking results; 3) By performing virtual amino acid mutations on the parent peptide obtained in step 2), a peptide library specifically binding to bisphenol A is constructed, and molecular dynamics is used for preliminary screening of the peptides; 4) The peptide chains screened in step 3) are used as specific recognition elements, and peptides labeled with fluorescein isothiocyanate are used to form specific recognition probes. The specific recognition probes are mixed with bisphenol A, and the peptide sequences with the strongest specific binding ability to bisphenol A are screened based on the different fluorescence differences. This invention is mainly applied to the screening of specific recognition elements for toxic and harmful small molecules, active ingredients, and functional factors. This method avoids the complex preparation steps of antibodies and the cumbersome screening process of aptamers, achieving high-throughput design of specific recognition elements.

The invention provides a ketoreductase mutant and application thereof. The ketoreductase mutant disclosed by the invention has amino acid mutations H39P and Y159F on the basis of an amino acid sequence as shown in SEQ ID NO.1, or has amino acid mutations S46T, D79G and V199A. The ketoreductase mutant provided by the invention can tolerate high-concentration acetone and high-concentration isopropanol, so that inhibition and damage of high-concentration acetone and isopropanol to enzyme can be relieved in the process of obtaining (R)-CHBE through catalytic reduction of COBE, the stability of the enzyme is improved, the service life of the enzyme is prolonged, and finally the substrate conversion rate and the product concentration are improved.

The application discloses a cyclodextrinase mutant and application thereof in glycosylation, and belongs to the technical field of genetic engineering. The cyclodextrinase and parent cyclodextrinase with more than 60% homology have one or more amino acid mutations in the peptide regions located at 45-52, 107-113, 163-166, 355-360, 374-376 and 465-468, or amino acid mutations occur at the equivalent positions of the parent cyclodextrinase, and a series of cyclodextrinase mutants with improved performance are provided. The mutant has at least any of the following improved performances: improved enzyme activity, improved product specificity, and reduced product hydrolysis rate, and can meet various requirements of practical application and research.

The invention belongs to the technical field of tobacco gene engineering, and particularly relates to a CCD4 protein mutant G312S and application thereof. Compared with a wild type CCD4 protein, the mutant has the following mutation: p. G312S, and the NCBI (National Center of Biotechnology Information) accession number of the wild type CCD4 protein is AKO22632.1. According to the invention, the substrate beta-carotene is docked to a CCD4 enzyme activity pocket, a saturated mutant library is constructed, screening is carried out through a bacterial color complementation experiment, and after specific site amino acid mutation, degradation of the substrate beta-carotene is accelerated, so that a certain technical foundation is laid for further cultivation of new varieties of tobacco crops.

The present invention relates to a viral vector capable of generating a cellular immune response against a spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), characterized in that the viral vector is a Newcastle disease virus (NDV) comprising a nucleotide sequence of SEQ ID NO: 6 or SEQ ID NO: 14 and an exogenous nucleotide sequence encoding antigenic sites of SARS-CoV-2, wherein the exogenous nucleotide sequence comprises a sequence having at least 95% sequence identity with a sequence that translates into the amino acid sequence of SEQ ID NO: 11, wherein the exogenous nucleotide sequence comprises an ectodomain of a SARS-CoV-2 S protein fused with a transmembrane domain and a cytoplasmic domain of an NDV fusion (F) protein, wherein the polybasic cleavage site of the ectodomain of the S protein is mutated to alanine and amino acids 817, 892, 899, 942,986 and 987 of the ectodomain of the S protein of SEQ ID NO: 11 are prolines, such that the viral vector and antigenic sites are stable after at least 3 consecutive passages in chicken embryo.

This invention provides a mutant phospholipase D for the efficient synthesis of phosphatidylserine, its products, and applications. The mutant is based on phospholipase D with the amino acid sequence shown in SEQ ID NO.1, obtained by mutating one or more of five sites at positions 87, 136, 189, 379, and 458 of this amino acid sequence. The amino acid mutation types at these sites include: L87E, M136G, I189R, E379L, and A458Y. This invention provides both a mutant phospholipase D and its applications. This mutant phospholipase D exhibits improved thermostability and catalytic activity, enabling the catalytic preparation of phosphatidylserine series products. The phosphatidylserine series products prepared using this enzyme can effectively alleviate metabolic syndrome induced by antipsychotic drugs.