6340results about "Transferases" patented technology

The invention discloses a biosynthesis system for high-yield 1, 6-hexamethylenediamine and application of the biosynthesis system, and belongs to the technical field of biology. According to the method, key genes which are excavated and optimized in a 1, 6-hexamethylenediamine biosynthetic pathway are co-expressed in a single cell module or a multi-cell module, and different enzyme elements expressed by the cell module are subjected to enzyme cascade reaction, so that 1, 6-hexamethylenediamine can be efficiently synthesized by taking caprolactam or 6-aminocaproic acid as a substrate; furthermore, after the carboxylic acid reductase MaCAR is mutated, the catalytic activity of the carboxylic acid reductase MaCAR can be remarkably improved, and the yield of the 1, 6-hexamethylenediamine is further improved; in addition, the biosynthesis system disclosed by the invention directly takes the cell module as a whole-cell catalyst, and an enzyme purification step is avoided, so that the biosynthesis system has the advantage of low cost.

The invention belongs to the technical field of RNA biological prevention and treatment, and particularly relates to dsRNA for preventing and treating crop anthracnose and application of the dsRNA. The dsRNA is targeted inositol phosphatidylceramide (IPC) synthetase coding gene dsRNA, and is obtained by transcription of a part of sequence (SEQ ID No.1) of an inositol phosphatidylceramide (IPC) synthetase coding gene CaAUR1, the gene segment is a segment of a target gene for preventing and treating crop anthracnose, and the dsRNA obtained by transcription can obviously reduce pathogenicity of mango anthracnose bacteria, and has the effects of keeping mango fresh, preventing and treating anthracnose. And the compound can be used for preventing and treating the crop anthracnose or preparing products for preventing and treating the crop anthracnose.

The invention discloses polyketide synthase or a polyketide synthase mutant and application thereof, and belongs to the technical field of gene engineering. The polyketide synthase is AspiPKS4, AspiPKS5, AspiPKS6 and AspiPKS7 from cyathea spinulosa, FhPKS2, FhPKS3, FhPKS4, FhPKS5 and FhPKS6 from ficus himalayana, and CrPKS from floating fern. The mutant is obtained by carrying out single point mutation on the second amino acid of AspiPKS7 or deleting an N-terminal redundant sequence. The polyketide synthase or the mutant is used for replacing NnHisspS in an original FBP luminescence system, and the biological self-luminescence level can be remarkably improved. The invention further provides a simplified and improved FBP system which comprises the polyketide synthase or the polyketide synthase mutant, CPH, H3H and Luz, and the application convenience and the application luminescence capacity of the FBP system are improved.

The invention discloses a glycosyl transferase mutant and an application of the glycosyl transferase mutant in synthesis of rebaudioside. According to the invention, single-point mutation and multi-point mutation are carried out on the basis of a glycosyl transferase amino acid sequence as shown in SEQ ID NO: 1, and a mutant with improved catalytic activity is obtained. The catalytic activity, the substrate specificity and / or the substrate specificity of the glycosyl transferase mutant are / is changed, and the catalytic activity of enzyme to a specific substrate can be remarkably improved by mutation at a specific site. And carrying out induced expression and protein purification on the obtained mutation sequence to obtain the mutant enzyme. The mutant enzyme is used as a catalyst, and UDPG is used as a glycosyl donor, so that the catalytic reaction efficiency of substrates such as stevioside ST, rebaudioside A (RebA) and rebaudioside D (RebD) can be obviously improved. According to the glycosyl transferase UGT76G1 mutant constructed by the research, the catalytic activity of the glycosyl transferase UGT76G1 mutant is improved, and efficient production of rebaudioside M is realized by optimizing a reaction system.

The invention relates to the technical field of genetic engineering, and particularly discloses a genetic engineering bacterium for producing melanin as well as a construction method and application of the genetic engineering bacterium. According to the application, the yield of the melanin can be effectively increased by modifying a metabolic pathway of the genetically engineered bacterium, and the yield of the melanin reaches 6.2 g / L and 18.5 g / L respectively through shake-flask culture and 5L fermentation tank culture. Compared with the prior art, the yield of melanin produced by the genetically engineered bacterium is improved by 30% at the shake flask fermentation level, the fermentation yield of a fermentation tank is improved by 4.3 times, in addition, expensive tyrosine is changed into glucose as a fermentation precursor substance, the production cost is greatly reduced, and an efficient and feasible solution is provided for large-scale production of melanin.

The invention belongs to the field of gene engineering, and particularly relates to application of an XC3225 gene in increasing the yield of xanthomonas campestris pv. Campestris xanthan gum. The invention finds that the XC3225 gene has a negative regulation effect on the xanthan gum yield, and the xanthan gum yield is remarkably improved by inhibiting or knocking out the XC3225 gene in the genome of xanthomonas campestris pv. Campestris, so that a new gene resource is provided for xanthan gum preparation.

The invention discloses a hemoglobin-resistant Taq DNA polymerase mutant and a construction method thereof, and relates to the field of biology, and the hemoglobin-resistant Taq DNA polymerase mutant is characterized in that a nucleotide sequence for coding the Taq DNA polymerase is shown as SEQ ID NO.1, and the mutant comprises at least one mutation or all mutations selected from S623D and E721A sites. On the basis of natural Taq DNA polymerase, the molecular structure of the Taq DNA polymerase is modified through rational design and combination with a site-specific mutagenesis biotechnology, so that the Taq DNA polymerase mutant is more suitable for PCR amplification of samples containing hemoglobin and the like than a wild type, and the result judgment accuracy of a sample containing a hemoglobin inhibitor is more facilitated.

The invention provides a recombinant strain for controllably synthesizing high-proportion 4-hydroxybutyric acid (4HB) polyhydroxyalkanoate (PHA) as well as a construction method and application of the recombinant strain. The recombinant strain disclosed by the invention can be used for efficiently producing high-proportion poly (3-hydroxybutyrate-4-hydroxybutyric acid) (P34HB for short) by using glucose as a unique carbon source or a 4HB structure related or non-related carbon source in amplification production of a shake flask, a 7L fermentation tank, a 100L fermentation tank and a 5000L fermentation tank.

The invention relates to the technical field of biology, in particular to a beta-1, 4-galactosyl transferase mutant and a method for biologically synthesizing lactose-N-neotetraose by using the beta-1, 4-galactosyl transferase mutant. The invention discloses a protein, which is a protein HpgalT-186 or a protein HpgalT-146-186, a protein HpgalT-146 and a protein HpgalT-146. The protein HpgalT-186 is a protein obtained by mutating an amino acid residue at the 186th site of a wild type HpgalT; the protein HpgalT-146-186 is a protein obtained by carrying out mutation on an amino acid residue at the 186 site and an amino acid residue at the 146 site of wild type HpgalT. On the basis, a series of escherichia coli is constructed and optimized, the yield of the LNnT synthesized through shake flask fermentation of the finally obtained strain reaches 1.73-4.1 g / L, the highest yield in a 5L fermentation tank reaches 20-45.2 g / L, and efficient synthesis of the LNnT is achieved.

Provided are S-adenosylmethionine synthetase mutants and the use thereof, belonging to the technical field of biological enzyme engineering. Site-directed combinatorial mutations are performed on positions 189, 200, 234, 266 and 371 of S-adenosylmethionine synthetase MAT to obtain a series of mutants with improved enzyme activity, wherein the specific enzyme activity of I189V / V266H and V266H / N371R is increased by more than 10 times relative to the parent. The yields of S-adenosylmethionine synthesized by whole cells of recombinant bacteria expressing mutants I189V / V266H / N371R, V266H / Q234N / N371R and I189V / V266H / Q234N / N371R all reach 1550 mg / L or more. The provided enzyme mutants have broad application prospects in the production of S-adenosylmethionine and the construction of genetically engineered microorganisms for S-adenosylmethionine.

The invention discloses an application of a medicago sativa MsDGK5 gene and a protein coded by the medicago sativa MsDGK5 gene in salt stress resistance of plants, and belongs to the technical field of plant genetic engineering. The nucleotide sequence of the medicago sativa MsDGK5 gene provided by the invention is as shown in SEQ ID NO. 1. According to the application, MsDGK5 gene overexpressed arabidopsis thaliana and medicago sativa transformation plants are constructed, growth and development indexes and physiological and biochemical parameters of the plants under salt stress are systematically measured, and it is proved that overexpression of the MsDGK5 gene can significantly improve the salt tolerance of the transgenic plants. Based on the experimental results, the key regulation effect of the MsDGK5 gene in plant salt tolerance is defined for the first time, an important gene resource is provided for crop salt tolerance genetic improvement, and a new technical approach is also provided for coping with the increasingly aggravated soil salinization problem.

Aspects of the disclosure relate to complexes and other aspects relate to formulations (e.g., aqueous, lyophilized forms) comprising such complexes comprising an oligonucleotide (e.g., useful for targeting DMPK) covalently linked to an antibody (e.g., anti-TfR1 antibody).

The invention relates to the technical field of biological catalysis, and discloses an L379A mutant enzyme for preparing rebaudioside I. The enzyme is obtained by the following mutations generated by UGT76G1: leucine of the 379th amino acid sequence is mutated into alanine; the enzyme can be applied to RA in-vitro conversion preparation of RI with higher utilization value, the conversion rate is higher than 50%, and the enzyme activity is remarkably improved by 7 times compared with the original enzyme catalytic conversion enzyme activity. The UGT76G1 mutant disclosed by the invention has the advantages that (1) the blank is filled, and a special enzyme catalyst capable of realizing efficient in-vitro synthesis of rebaudioside I (RI) is provided for the first time; 2) efficiency jump: the catalytic conversion rate is greatly increased from original about 7% to more than 50% (increase gt; and 3) stability and reliability: in the cross-scale reaction of 10mL to 5L, the catalyst has stable catalytic performance, shows excellent industrial application potential, and is suitable for popularization and application.

Aspects of the disclosure relate to complexes and other aspects relate to formulations (e.g., aqueous, lyophilized forms) comprising such complexes comprising an oligonucleotide (e.g., useful for targeting DMPK) covalently linked to an antibody (e.g., anti-TfR1 antibody).

The invention specifically discloses a composition for detecting NAD < + > and application thereof, and relates to the technical field of biological detection. According to the composition for detecting NAD < + >, the composition comprises an NAD < + > binding protein fragment A connected with an Fc tag, an NAD < + > binding protein fragment B and a connecting peptide, the detection result is accurate and reliable, and meanwhile the technical difficulty, uncertainty and high cost faced by antibody screening in a traditional method are avoided.

The present invention discloses a gene, GmCDK8, that negatively regulates soybean resistance to Phytophthora spp., and its applications. The disclosed GmCDK8 knockout soybean plants exhibit enhanced resistance to the fungus. Specifically, the results of the soybean cultivar "Williams 82," which lacks GmCDK8, under Phytophthora stress, including root lesion length, leaf lesion area, Phytophthora accumulation, and infected necrotic area on leaves, indicate that knocking out GmCDK8 significantly improves plant resistance to Phytophthora spp. Genetic engineering of this gene for plant resistance to Phytophthora root rot not only provides an important genetic resource for plant molecular breeding but also offers an effective means for achieving high plant yields.

The invention relates to a diacylglycerol acyltransferase mutant and application thereof in synthesis of triacylglycerol from saccharomyces cerevisiae, and belongs to the technical field of enzyme engineering. Diacylglycerol acyltransferase is a rate-limiting step of a synthetic route of saccharomyces cerevisiae triacylglycerol (TAG), and at present, a research on a DGA1 mutant for efficiently synthesizing TAG is lacked, and a research on the aspect of a DGA1 catalytic mechanism is also lacked. The DGA1 mutant capable of effectively improving TAG synthesis is obtained by screening in combination with a directed evolution technology, and a result shows that 282-site mutation of diacylglycerol acyltransferase can significantly increase the accumulation amount of TAG. Meanwhile, the catalytic mechanism of the DGA1 is preliminarily explored by combining protein structure prediction, molecular docking and molecular dynamics simulation, and a foundation is laid for deeply analyzing the catalytic mechanism of the DGA1. The recombinant saccharomyces cerevisiae is also constructed based on the mutant, so that the TAG synthesis is improved, and meanwhile, the relative proportion of C18: 1 in total fatty acids is remarkably increased.

The invention provides an RNA polymerase variant and application thereof, and relates to the technical field of biology, the enzyme specific activity of the variant is obviously improved compared with that of a wild type, and the addition amount of polymerase is reduced, so that the cost is saved. Meanwhile, the mutant also effectively reduces the generation of incomplete fragment impurities and improves the integrity. In addition, the invention further provides a method for generating RNA through in-vitro transcription.

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 present disclosure provides compositions and methods for the targeted modification of RNA molecules by RNA prime editing. The compositions and methods may be conducted invitro or in vivo within cells (e.g., human cells) for the therapeutic correction of disease-causing mutations and / or installation of motifs or mutations in RNA molecules of interest as a tool for scientific research. The disclosure provides compositions and methods for conducting RNA prime editing of a target RNA molecule (e.g., an RNA transcript) that enables the incorporation of one or more nucleotide changes and / or targeted mutagenesis of a target RNA molecule. The nucleotide change can include a single-nucleotide change, an insertion of one or more nucleotides, or a deletion of one or more nucleotides. More in particular, the disclosure provides a variety of configurations of the RNA prime editors each comprising a nucleic acid programmable RNA binding proteins (napRNAbp), such as Cas13, and an RNA-dependent RNA polymerase (RDRP), which are provided as fusion proteins or which can be separately provided in trans. The RNA prime editors are guided to a target RNA site by a guide RNA, which can be a rpegRNA that includes a template region for the synthesis of an RNA sequence to be installed on the RNA molecule attached to an available 3′ terminus. In others embodiments, the RNA template can be provided in trans.

Methods for producing a linear deoxyribonucleic acid (DNA) product with enhanced resistance to nuclease digestion are provided. The methods comprise, (a) digesting a double-stranded DNA molecule with an endonuclease that cleaves an endonuclease target sequence to generate a digested double-stranded DNA molecule, wherein the digested double-stranded DNA molecule comprises a linear double-stranded region, and a truncated protelomerase sequence at a first end, wherein the truncated protelomerase target sequence is non-functional; (b) appending a first adaptor molecule to the first end of the digested double-stranded DNA molecule and appending a second adaptor molecule to the second end of the digested double-stranded DNA molecule to generate a precursor double-stranded DNA molecule, wherein the first adaptor molecule comprises a truncated protelomerase target sequence that forms a first functional protelomerase target sequence with the truncated protelomerase sequence at the first end of the digested double-stranded DNA molecule; and (c) incubating the precursor double-stranded DNA molecule with a protelomerase to generate the linear DNA product, wherein the protelomerase closes the first end of the precursor double-stranded DNA molecule at the first functional protelomerase target sequence.

The invention relates to the technical field of biological catalysis, and discloses an M88V mutant enzyme for preparing rebaudioside I. The M88V mutant enzyme is obtained by the following mutations generated by UGT76G1: M88V: methionine of the 88th amino acid sequence of UGT76G1 is mutated into valine. Aiming at the technical bottlenecks of low RI yield and poor selectivity in the existing RA biotransformation process, an efficient solution is provided for the UGT76G1 mutant developed by the invention. The mutant can specifically catalyze conversion from RA to RI, and the conversion rate of a target product is remarkably increased to 65% or above from general less than 7%. The excellent catalytic performance of the catalyst is verified in milliliter-level to upgraded reaction systems, the key problems of conversion efficiency and process amplification are solved, and a foundation is laid for large-scale green manufacturing of a high-added-value product RI.

The invention provides an RNA polymerase variant and application thereof, and relates to the technical field of biology. Wild type T7 RNA polymerase is modified to obtain the T7 RNA polymerase variant, the enzyme specific activity of the T7 RNA polymerase variant is remarkably improved compared with that of the wild type T7 RNA polymerase, the addition amount of the polymerase in the in-vitro transcription reaction process can be reduced, and the cost is saved; in addition, the mutant also effectively reduces the generation of incomplete fragment impurities, and the mRNA integrity is significantly improved to 99%. The invention further provides a method for preparing RNA through in-vitro transcription.

The invention discloses a Taq DNA polymerase mutant as well as a preparation method and application thereof, and relates to the technical field of biology. The Taq DNA polymerase mutant is mutation on the basis of a wild type Taq DNA polymerase amino acid sequence as shown in SEQ ID NO.1, and comprises at least one of amino acid mutation L345E, L352D and S438M. The Taq DNA polymerase mutant has excellent tolerance to urea, and solves the dual technical problems that complex biological samples containing endogenous inhibitors such as urea can be efficiently amplified, and the Taq DNA polymerase mutant is compatible with difficult PCR reactions which take urea as an additive to optimize a high GC template and the like. Therefore, the mutant is a molecular biology tool enzyme which is wider in applicability and more stable and reliable in performance.

The disclosure provides, for example, double stranded DNA (dsDNA) molecules comprising one or more chemically modified nucleobases. In some embodiments, the dsDNA molecule is circular and comprises a first strand and a second strand, wherein the first strand comprises one or more chemically modified nucleobases, and the second strand is free of chemically modified nucleobases. In some embodiments, the dsDNA molecule comprises a promoter sequence and an effector sequence that encodes an effector.

The invention belongs to the field of gene engineering and enzyme engineering, and particularly relates to a method for producing rebaudioside M by an enzyme method. The method comprises the following steps: S1, adding a mixed solution 1 of recombinant cell disruption liquid into a substrate, adding into a buffer solution to obtain a pre-reaction solution 1 (a mixture of recombinant cell disruption liquid of a recombinant strain UGT11 (S158F) and a recombinant strain AtSUS (P94N)), and collecting precipitate after reaction; and S2, after the precipitate is dissolved, adding a mixed solution 2 (a mixture of recombinant cell disruption solutions of a recombinant strain UGT76G1 (G83Q) and a recombinant strain AtSUS (P94N)) of recombinant cell disruption solutions, adding a buffer solution to obtain a pre-reaction solution 2, and collecting the reaction solution to obtain Reb M. The method provided by the invention can effectively solve the problems of low content and poor specificity of the extracted Reb M, and can realize the conversion rate of 93.33% from Reb A to Reb M.

The invention belongs to the field of biosynthesis, and in particular relates to LBD (Levandanenediol Pyrophosphate) synthase and engineered yeast for producing sclareol. In order to solve the problem that in the prior art, the sclareol biosynthesis yield is generally low, LSLPPs mutant containing at least one mutation of D730L, D374L, N674L or G379M is obtained by performing mutation and optimization on LSLPPs pyrophosphate synthase, and the mutant is used for sclareol synthesis. Meanwhile, in order to solve the problem of genetic instability caused by free plasmid expression of part of saccharomyces cerevisiae strains, a sclareol synthesis pathway is constructed in a yeast genome, and meanwhile, an acetyl coenzyme A synthesis pathway, an MVA pathway and a sclareol synthesis pathway are enhanced; chassis bacteria for synthesizing sclareol are modified in a manner of knocking out part of transcription inhibition factors, and the yield of a 5L fermentation tank reaches 26.11 g / L and is greatly improved compared with the prior art.

The invention discloses a spermidine synthetase mutant and application of the spermidine synthetase mutant in synthesis of spermidine, and belongs to the technical field of genetic engineering and metabolic engineering. According to the method, the spermidine synthetase is mutated firstly, the efficiency of the spermidine synthetase is improved, and on the basis, the dissolved oxygen and fed-batch concentration are optimally controlled through fermentation, so that the yield of spermidine is improved. The corynebacterium glutamicum provided by the invention is an engineering bacterium with plasmids and without defects, and after the corynebacterium glutamicum is subjected to fed-batch fermentation in a 5L fermentation tank for 68 hours, the yield of spermidine reaches 25.1 g / L, and the sugar-acid conversion rate is 17.9%.

The invention belongs to the field of biosynthesis, and particularly relates to sclareol synthase and engineered yeast for producing sclareol. In order to solve the problem that in the prior art, sclareol biosynthesis yield is generally low, sclareol synthase is mutated and optimized, an SsScs mutant containing at least one mutation of Y491F, G307L or N269F is obtained, and the mutant is used for sclareol synthesis. Meanwhile, in order to solve the problem of genetic instability caused by free plasmid expression of part of saccharomyces cerevisiae strains, a sclareol synthesis pathway is constructed in a yeast genome, and meanwhile, an acetyl coenzyme A synthesis pathway, an MVA pathway and a sclareol synthesis pathway are enhanced; chassis bacteria for synthesizing sclareol are modified in a manner of knocking out part of transcription inhibition factors, and the yield of a 5L fermentation tank reaches 21.13 g / L and is greatly improved compared with the prior art.

The invention relates to the technical field of synthetic biology, metabolic engineering and cell culture. The present invention provides a cell for the production of a negatively charged, preferably sialylated, oligosaccharide wherein the cell is genetically engineered to have or express, preferably overexpress, a hydrolytic UDP-N-acetyl-D-glucosamine-2-epimerase. The invention further provides the use of said cells in culture or incubation. Also described are methods of producing negatively charged, preferably sialylated oligosaccharides using the cells, and purification of the negatively charged, preferably sialylated oligosaccharides.