365 results about "Site-directed mutagenesis" patented technology

The invention discloses a high-stability hydroxysteroid dehydrogenase mutant, a co-immobilized enzyme construction method and application. According to the invention, a site-directed mutant library is constructed based on computer-aided design, and mutants with significantly improved thermal stability and greatly improved catalytic efficiency compared with wild type mutants are obtained through screening; meanwhile, a co-immobilized enzyme construction method based on electrostatic adsorption and chemical crosslinking is established, the hydroxysteroid dehydrogenase mutant and lactic dehydrogenase are co-immobilized, the co-immobilized enzyme can still keep high activity under high substrate concentration, and the conversion rate is still maintained to be 90% or above after 30 batches of co-immobilized enzyme are repeatedly used. And an important foundation is laid for industrial application of the hydroxysteroid dehydrogenase.

The invention belongs to the technical field of microbial genetic engineering, and particularly relates to an alpha-2, 3-sialyltransferase mutant and application thereof. The a-2, 3-sialyltransferase mutants V175N, P198A, G173D, D174Q, F196K and A315H are obtained by performing site-specific mutagenesis on six amino acids in an a-2, 3-sialyltransferase amino acid sequence coded by a gene derived from Campylobacter jejuni (OH4384), the yield of 3 '-sialyllactose is remarkably increased by single-point mutagenesis of the V175N, the yield of 3'-sialyllactose is remarkably increased by single-point mutagenesis of the V175N, the yield of 3 '-sialyllactose is remarkably increased by single-point mutagenesis of the P198A, the G173D, the D174Q, the F196K and the A315H, the optimal recombinant microbial strain 3 '-SL-09 (V175N / P198A / D174Q) is obtained through combination of multiple mutation sites, the yield can reach 5.91 g / L, the bottleneck problem of low catalytic efficiency of sialyltransferase is effectively solved, and an enzyme element with excellent performance is provided for high-efficiency and low-cost biological manufacturing of 3'-SL.

The invention discloses a D-psicose 6-phosphate phosphatase mutant and application of the D-psicose 6-phosphate phosphatase mutant in preparation of psicose, and belongs to the technical field of enzyme engineering. According to the invention, site-directed mutagenesis is carried out on an amino acid sequence of D-psicose 6-phosphate phosphatase A6PP, and a combined mutant I21V / Y73F / R115M / T180V / L203I / Q193E is constructed, so that the substrate specificity, the thermal stability and the catalytic activity of the combined mutant are all remarkably improved. The invention further provides application of the combined mutant in preparation of psicose through multi-enzyme cascade catalysis, 150 g / L of maltodextrin can be converted into 97.7 g / L of D-psicose, the conversion rate reaches 65.1%, and the application prospect of the combined mutant in the field of food is widened.

The invention discloses application of an upstream non-coding region uORF of an ABA2 gene in regulation and control of crop agronomic traits, in particular to application in improvement of pre-harvest sprouting resistance of rice and cultivation of pre-harvest sprouting resistant rice strains, and belongs to the technical field of gene engineering. The invention finds that uORF in the upstream non-coding region of the crop ABA2 gene can inhibit the translation level of downstream ABA2 protein on the basis of not influencing the transcriptional level, so that the uORF can participate in regulation and control of crop agronomic traits in which ABA participates in regulation and control, such as improvement of pre-harvest sprouting resistance of rice. Therefore, the upstream non-coding region uORF of the crop ABA2 gene can be modified through a hybridization or gene editing technology, so that the purpose of regulating and controlling crop agronomic traits in which ABA participates in regulation and control is achieved, for example, site-directed mutagenesis is performed on an initiation codon of the upstream non-coding region uORF of the rice ABA2 gene, and the pre-harvest sprouting resistance of rice is improved.

The application relates to an engineering bacterium for high yield of observation blue and a construction method and application thereof, and belongs to the technical field of biological synthesis of natural dyes. The engineering bacterium for high yield of observation blue expresses icd, bpsA, glnA Y405F and gdhA; the engineering bacterium knocks out acnR, yggB, glsK, aceA and ldh. By knocking out the yggB and aceA genes, performing site-directed mutation (Y405F) on the glnA gene, replacing the glsK gene with the glnA Y405F gene, replacing the acnR gene with the icd gene, replacing the ldh gene with the gdhA gene, and integrating the bpsA gene, the application can block the formation of by-products such as lactate and succinic acid in the observation blue synthesis process, improve the flow direction of the citric acid->isocitric acid->alpha-ketoglutaric acid->glutamic acid->glutamine path, and then improve the intracellular glutamine concentration, so that the yield of observation blue is improved.

According to the invention, a glycosyl transferase mutant derived from Bacillus licheniformis ZSP01 is used as a research object, AlphaFold 2 is used for constructing a three-dimensional structure of a protein, then technologies such as molecular docking and molecular dynamics simulation are used for analyzing amino acids far away from a catalytic center in glycosyl transferase, site-directed mutagenesis is carried out on the amino acids, and the glycosyl transferase is obtained. The activity of the mutant for catalytically synthesizing the icariside D2 glycosyltransferase is improved.

The invention discloses a male sterility gene ZmUCE4 and application thereof in creating a male sterility line of corn, and belongs to the field of plant biotechnology breeding. According to the invention, site-directed mutagenesis of the ZmUCE4 gene in wild type corn is carried out through a CRISPR / Cas9 gene editing technology, pollen development abnormality and abortion can be caused, complete male sterility is caused, and it is proved that the ZmUCE4 gene has a regulation and control function on corn male reproductive development. Through offspring screening, a sterile line without transgenic components can be obtained, a stable maize male sterile line is created, and the method has important significance on maize male fertility control and hybrid seed production. The invention also designs a functional molecular marker aiming at the obtained uce4 male sterility mutant gene, and has important application value in maize male sterility line cultivation, sterile hybrid seed production and molecular marker-assisted selection.

According to the invention, glycosyl transferase UGTBL1 derived from Bacillus licheniformis ZSP01 is taken as a research object, AlphaFold 2 is used for modeling, molecular docking, molecular dynamics simulation and other technologies, amino acid in an active pocket region of glycosyl transferase is analyzed, amino acid in a substrate channel is analyzed by software CAVER3.0, site-directed mutagenesis is carried out, and the glycosyl transferase UGTBL1 is obtained. The regioselectivity and the activity of the mutant for catalytically synthesizing the icariside D2 glycosyltransferase are improved.

The invention belongs to the technical field of biosynthesis, and particularly relates to a strain for producing sclareol as well as a construction method and application of the strain. In order to solve the problem of microbial synthesis of sclareol, phosphoketolase in an NOG pathway is mutated and optimized, phosphoketolase NaXpk from nanoarchaea archaeon is subjected to site-directed mutagenesis, a sclareol synthesis pathway is constructed in an escherichia coli host, the influence of NaXpk before and after mutation on the yield of sclareol is compared, and the yield of sclareol is improved. The S472F mutant and the S472Y mutant are determined, the S472F mutant and the S472Y mutant are applied to a sclareol production path, the sclareol yield of the finally obtained production strains can reach 623.3 mg / L and 655.2 mg / L, and the effect is remarkable.

According to the present invention, glycosyl transferase UGTBL1 derived from Bacillus licheniformis ZSP01 is adopted as a research object, AlphaFold 2 is adopted to carry out modeling, molecular docking, molecular dynamics simulation and other technologies, amino acids in an active pocket region of glycosyl transferase are analyzed, site-directed mutagenesis is performed on the amino acids to obtain a series of glycosyl transferase mutants, and salidroside can be highly selectively catalyzed and synthesized.

The application discloses a kind of fungal laccase mutant Lcc5-G and its expression strain and application.The application is based on the fungal laccase from Coprinopsis cinerea heterologous expression since, by site-directed mutagenesis, obtain mutant gene.After fungal induction expression containing mutant plasmid, obtain laccase mutant enzyme Lcc5-G with improved specific activity, stability and AFB1 removal efficiency.When ABTS is used as substrate, the specific activity of the mutant is improved by 3 times, and the stability of the mutant enzyme is improved to 5 times of the original enzyme at 45 DEG C and pH 7.The mutant has potential application value in oxidizing aflatoxin.

The invention provides a 2-succinyl-5-enol acetonyl-6-hydroxy-3-cyclohexene-1-carboxylic acid (SEPHCHC) synthase mutant, which is characterized in that on the basis of a bacillus subtilis SEPHCHC synthase gene MenD, 12 SEPHCHC synthase mutants are obtained by virtue of a site-specific mutagenesis PCR (Polymerase Chain Reaction) technology, and the SEPHCHC synthase gene MenD is used as a base. Recombinant bacteria of bacillus subtilis or bacillus natto or bacillus licheniformis or bacillus amyloliquefaciens for expressing the mutant are respectively constructed, and the yield of heptaene menadione fermented by the recombinant bacteria is 74%-203% of the yield of heptaene menadione fermented by the recombinant bacteria of bacillus subtilis for expressing wild type SEPHCHC synthase MenD.

According to the scheme, the invention provides the recombinant macrolide enzyme as well as the preparation method and the application thereof, the amino acid sequence of the recombinant macrolide enzyme is as shown in SEQ ID NO.1, and the recombinant macrolide enzyme is derived from an EreC esterase family of enterobacter hormaechei and is obtained through site-specific mutagenesis; the mutation sites are as follows: glutamic acid at the 44th site is mutated into asparagine, tyrosine at the 55th site is mutated into proline, proline at the 76th site is mutated into arginine, phenylalanine at the 153rd site is mutated into alanine, and serine at the 219th site is mutated into glutamic acid. The method is expected to remove macrolide antibiotic pollution, and has good economic benefits and practical values.

Disclosed in the present invention are a sucrose synthase mutant and a method for preparing RD using same. The sucrose synthase mutant is based on the amino acid sequence shown in SEQ ID NO: 2 and contains a mutation in at least one of the following sites: D296Q, R636Q, G514L, H531L, R567T, D569Q, E610N, A642N, E663N, L667T and T742R. By means of site-directed mutagenesis of sucrose synthase, the enzyme activity of the sucrose synthase mutant is improved compared with that of the wild type. Also, some mutants can still maintain a high conversion rate in a wide pH range.

The application provides a preparation method of a functionalized phage probe and application of the functionalized phage probe in detection of escherichia coli. The functionalized phage is a recombinant phage (M13KO7@SaBP) in which streptavidin binding peptide (SaBP) is fused and expressed at the N terminal of the main capsid protein P8 protein of M13K07 phage. In the application, the gene encoding SaBP (MDVEAWLGAR) is inserted into the N terminal of the P8 protein gene of M13K07 phage by site-directed mutagenesis to prepare M13K07@SaBP. The stable signal amplification is realized by using the abundant P8 protein (about 2700) of M13 phage and the super strong binding force of biotin-streptavidin, the interference of food sample matrix is reduced by combining the magnetic separation technology, and a detection method of escherichia coli with high sensitivity and small sample matrix interference is constructed.

The invention belongs to the technical field of microbial genetic engineering, and particularly relates to an alpha-2, 6-sialyltransferase mutant and application thereof. The a-2, 6-sialyltransferase mutants M133L, E140D, D228H, N289D and G322Q are obtained by carrying out site-specific mutagenesis on five amino acids in an a-2, 6-sialyltransferase amino acid sequence coded by a gene derived from Photobacterium sp.JT-ISH-224, and compared with wild type alpha-2, 6-sialyltransferase, the yield of the single-point mutant 6 '-SL of the E140D and the yield of the single-point mutant 6'-SL of the G322Q are increased by 87.80% and 78.01% respectively. The yield of the optimal recombinant microbial strain 6 '-SL-7 (E140D / G322Q) obtained by mutation site combination can reach 1.471 g / L, the bottleneck problem of low catalytic efficiency of sialyltransferase is effectively solved, and an enzyme element with excellent performance is provided for high-efficiency and low-cost biological manufacturing of 6'-SL.

The invention relates to a beta-galactosidase mutant with improved thermal stability and pH stability, and belongs to the technical field of enzyme engineering. The beta-galactosidase derived from Kluyveromyces lactis is subjected to molecular modification, a potential mutation site is determined by using an alanine scanning strategy, beta-galactosidase mutants Pro433Ala and Asp441Ala of which the thermal stability and the pH stability are simultaneously improved are obtained through site-directed mutagenesis screening, the catalytic efficiency of the mutants is improved to 1.03-1.18 times compared with that of the mutants before optimization, and the beta-galactosidase mutant can be used for preparing beta-galactosidase. Wherein the maximum half-life period of the mutant Asp441Ala under the condition of 50 DEG C reaches 91.5 minutes and is increased by 213.4% compared with that of a wild type, the problems of poor catalytic thermal stability and poor pH stability of beta-galactosidase in the prior art are solved, and a brand-new tool is provided for obtaining galactooligosaccharide by using beta-galactosidase to hydrolyze lactose.

The invention provides a tyrosine ammonia lyase mutant and application thereof in production of p-coumaric acid. The tyrosine ammonia lyase mutant is obtained by mutating wild type tyrosine ammonia lyase with an amino acid sequence as shown in SEQ ID No.1, and a mutation site is selected from at least one of Q108S, Y340Q and P375H. The catalytic activity center of wild type tyrosine ammonia lyase is analyzed, and site-directed mutagenesis is carried out on five catalytic activity center sites, so that the mutant shows different enzyme catalytic activity when the mutation sites are different, the mutation sites are the same but the mutation targets are different; q108S, Y340Q and P375H single mutations can significantly improve the enzyme catalytic activity of the tyrosine ammonia lyase mutant, and the tyrosine ammonia lyase mutant having any two mutation sites, especially having three mutation sites, also has better enzyme catalytic activity than the wild type, and has great application potential.

The invention relates to the technical field of bioengineering, in particular to a penicillin G acylase mutant, polynucleotide, an expression vector and application. The penicillin G acylase mutant is obtained by carrying out site-directed mutagenesis on a wild type penicillin G acylase gene of parent Escherichia coli, and carrying out site-directed mutagenesis on the wild type penicillin G acylase gene to obtain the penicillin G acylase mutant. Phenylalanine (F) at the 24th site of an alpha chain, proline (P) at the 383rd site of a beta chain, threonine (T) at the 384th site of the beta chain, glutamic acid (G) at the 385th site of the beta chain and serine (S) at the 386th site of the beta chain of the penicillin G acylase are introduced and mutated by a whole plasmid PCR (Polymerase Chain Reaction) technology to obtain mutants. When the penicillin G acylase mutant obtained by the invention is used for catalyzing methyl mandelate and 3-(1-methyl-1H-tetrazole-5-yl) thiomethyl-7-aminocephalosporanic acid to synthesize cefamandole, the synthesis activity is improved, and meanwhile, the side reaction rate is greatly reduced.

The invention relates to the field of biosynthesis of glycosaminoglycan compounds, and discloses a 2-O-sulfotransferase mutant and application of the 2-O-sulfotransferase mutant in heparin synthesis. On the basis of a chicken source 2-O-sulfotransferase protein sequence, site-directed mutagenesis design and modification are carried out, mutation sites comprise 6I, V60I, R120K, G118H, S157H, L227P, E270D, V258I and A275P, and the 2-O-sulfotransferase mutant is obtained. Compared with a wild type, the 2-O-sulfotransferase mutant provided by the invention has the advantages that the expression level, the thermal stability and the catalytic efficiency are obviously improved, and the 2-O-sulfotransferase mutant shows higher conversion rate and structural modification consistency in a reaction system taking N-sulfoheparin precursor polysaccharide as a substrate. The mutant has a wide application prospect in the structural precise control and industrial synthesis process of biological heparin.

The invention discloses a polypeptide (NP1706, SEQ ID NO: 6) derived from the skin of nanorana parkeri, a polypeptide derivative as well as a composition and application of the polypeptide derivative. A natural parent peptide (NP1711, SEQ ID NO: 11) is optimized by combining a polypeptide activity prediction system with a molecular design technology, systematic mutation screening finds that the 5th site, the 9th site and the 14th site are active non-essential residues, and variant derivatives obtained by performing site-directed mutagenesis on the 5th site, the 9th site and the 14th site do not significantly change the original biological activity. The pharmacological activity and safety parameters of the NP1706 show optimal balance, so that the NP1706 is determined as the optimal candidate polypeptide. Based on the polypeptide and the polypeptide derivative, the activities of promoting cell proliferation and migration, resisting oxidation, resisting inflammation and the like are provided, and the application of the polypeptide and the polypeptide derivative in cosmetics and medicines is provided. The invention has the advantages of simple synthesis, good safety and excellent biological activity, and can be widely applied to the fields of skin repair, aging resistance, wound healing, inflammation resistance and the like.

The invention discloses construction and application of a Primrose syndrome non-human animal model, and belongs to the technical field of animal models and disease research. According to the invention, through a CRISPR / Cas9 technology, a codon CAC for coding 596th histidine in a No.14 exon of a mouse Zbtb20 gene is subjected to site-directed mutagenesis into CGC for coding arginine, and a hybrid mouse model for simulating pathogenic point mutation (p.H596R) of human Primrose syndrome is constructed. The model can stably reproduce key clinical phenotypes of the Primrose syndrome, including overgrowth after adult, serum IGF-1 rise, memory dysfunction and anxiety behaviors, and shows abnormal hippocampal neuronal development and synaptic transfer related pathways and the like. The invention provides an important experimental tool for deeply revealing the pathological mechanism of Primrose syndrome, developing drug screening and treatment intervention research and the like.

The invention belongs to the technical field of enzyme gene engineering, and particularly relates to a methionine gamma-lyase mutant with improved enzyme activity and application thereof. The methionine gamma-lyase mutant CqMGLV160I / V265I with high activity is obtained by taking methionine gamma-lyase (CqMGL) which is derived from Calorama quimayensis and of which cysteine residues at 116 sites are replaced by histidine residues as a parent and carrying out site-specific mutagenesis on amino acid residues at key sites through transformation. The methionine gamma-lyase mutant CqMGLV160I / V265I with high activity can be obtained by using the methionine gamma-lyase mutant CqMGLV160I / V265I as the parent. By adopting the CqMGLV160I / V265I mutant disclosed by the invention, the conversion rate of enzyme catalysis can be improved, allicin is efficiently synthesized, and the mutant is successfully applied to the aspects of food, feed, chemical industry, medicine preparation and the like.

This invention relates to the field of enzyme engineering technology, and in particular to a highly efficient lactone hydrolase mutant for degrading zearalenone and its applications. This lactone hydrolase mutant uses the lactone hydrolase gene from Monosporascus sp. GIB2 as a template, and performs a site-directed mutation at amino acid position 134 to obtain L134A, L134V, L134I, and L134M mutants. Under optimal conditions of pH 9.0 and 60℃, these single-point mutants can efficiently degrade zearalenone (ZEN) within 3 minutes. The enzyme activity for degrading zearalenone is significantly improved compared to the original enzyme, with degradation activities increasing by 1.22 (L134A), 1.25 (L134V), 1.17 (L134I), and 1.14 (L134M), respectively, demonstrating significant applications and economic value in the feed industry.

The application provides an arginine mutant and application thereof in 1,4-butanediamine biosynthesis, and belongs to the field of bioengineering. Escherichia coli The mutant is obtained by site-directed mutagenesis of key site amino acid residues based on wild-type EcAdiA from strain The application improves the enzyme activity stability of arginine decarboxylase in neutral environment, improves the conversion rate and conversion speed of 1,4-butanediamine in neutral environment, and lays a foundation for high-efficiency biosynthesis of 1,4-butanediamine.

This invention relates to the fields of microbial genetic engineering and fermentation biomanufacturing technology, specifically disclosing a recombinant Corynebacterium glutamicum with high 5-aminolevulinic acid (ALA) production and its applications. Addressing the problems of existing strains such as crude enzyme activity regulation, inhibited cell growth, the need for external inhibitors, and low yield, this invention uses Corynebacterium glutamicum as a host and removes the gdhA gene without scarring to reduce precursor competitive metabolism. Site-directed mutations of the endogenous hemB gene (S288A, D128E, R231K) are performed to moderately reduce dehydratase activity. A high-expression plasmid pXMJ19-hemA containing the hemA gene from Rhodopsinus capsulatum is constructed and introduced into the modified strain to obtain a recombinant strain with optimized triple metabolism. This strain reduces product degradation without the need for external dehydratase inhibitors, does not affect cell growth, and achieves a yield up to 4.30 times higher than the control after 42 hours of fermentation, with ALA accumulation exceeding 8.9 g / L. The strain exhibits stable characteristics, the process is simple, and it has good industrial application value.

The invention discloses a sucrose synthase mutant and a method for preparing RD (Reduced Disorder) by using the sucrose synthase mutant. The sucrose synthase mutant is obtained by mutation of at least one of the following sites on the basis of an amino acid sequence as shown in SEQ ID NO: 2: D296Q, R636Q, G514L, H531L, R567T, D569Q, E610N, A642N, E663N, L667T and T742R; site-directed mutagenesis is carried out on sucrose synthetase, so that the enzyme activity of the sucrose synthetase mutant is improved compared with that of a wild type, and meanwhile, a part of the mutant still maintains a relatively high conversion rate in a relatively wide pH range.

The application discloses a thermophilic bacteria-derived esterase mutant and application thereof. The application provides a protein, wherein the amino acid residue at the 211th position in the amino acid sequence shown in SEQ ID NO: 4 is mutated, and the amino acid residues at other positions are not changed, so that a protein with PBAT hydrolytic enzyme activity is obtained; or the amino acid residues at the 211th and 256th positions in the amino acid sequence shown in SEQ ID NO: 4 are mutated, and the amino acid residues at other positions are not changed, so that a protein with PBAT hydrolytic enzyme activity is obtained; the wild type Tcur-lipase is mutated by using structure analysis and site-directed mutagenesis technology, and the Tcur-lipase mutants N211A and N211A / D256A are obtained; the Tcur-lipase mutant improves the degradation efficiency of PBAT, and has a good industrial application prospect.

The invention relates to the technical field of biological medicines, in particular to a preparation method of an inhibitor targeting a MAX-PD-L1 promoter specific binding motif and a double-target inhibitor, through ChIP-seq and site-directed mutagenesis experiments, a core binding motif of MAX and a PD-L1 promoter, such as 5 '-CAC [GA] TG-3', is defined, it is ensured that the inhibitor only targets a key site of MAX-PD-L1 interaction, and the activity of the MAX-PD-L1 promoter specific binding motif is improved. The off-target effect is avoided, and a high-specificity target spot is provided for subsequent inhibitor design. The cell permeability of the DNA aptamer screened based on the specific binding motif is improved after cholesterol modification, and the affinity of the DNA aptamer is obviously higher than that of a traditional antibody. A small molecule compound virtually screened through a molecular docking model is optimized through hydrogen bond and hydrophobic interaction, and then the binding affinity with MAX is improved. After treatment with the inhibitor, the combination inhibition rate of MAX and the PD-L1 promoter is high, the transcriptional activity of PD-L1 is obviously reduced, the killing rate of T cells to tumor cells is also improved, and immune escape is effectively blocked.

The invention discloses an Apopsin3 mutant and a method for regulating an environment in a plant cell to be acidic, and belongs to the technical field of pH regulation in the plant cell. The regulation and control method comprises the following steps: mutating 83rd and 120th amino acids of the light-operated hydrogen ion pump protein Apopsin3, converting into hydrogen ion channels, expressing the hydrogen ion channels on a cell membrane in a targeting manner, and stimulating with green light of 40-500 [mu] W / mm < 2 > and 520-560 nm so as to regulate the pH in the cell to be acidic. By adopting the cell specific promoter and performing site-specific mutagenesis modification on the specific hydrogen ion pump, accurate pH regulation and control on specific cells or organelles can be realized. An Apopsin3 (FARH) gene is fused with a cell membrane targeting sequence, and under the stimulation of specific light, only the pH of cytoplasm is obviously changed, and the pH of other cell regions is not influenced.