689 results about "Valine" patented technology

The invention relates to a fluorescent protein selection marker staygold-levEr gene as well as a construction method and application thereof, and belongs to the technical field of biological engineering. The invention provides a fluorescent protein selection marker staygold-levEr gene for screening an L-valine production strain and a construction method of a gene fragment, compared with other similar gene selection markers, the selection marker provided by the invention has the advantages that the fluorescence intensity is positively correlated with the concentration of L-valine, and the screening marker has the advantages that the screening marker can be used for screening the L-valine production strain; according to the screening marker, the screening efficiency of the L-valine high-yield strain can be obviously improved, the screening time and cost can be saved, the screening efficiency can be improved, and the screening marker has a wide application prospect.

The invention discloses a formate dehydrogenase mutant and application thereof in catalytic synthesis of D-mannitol, and belongs to the technical field of bioengineering. According to the formate dehydrogenase mutant provided by the invention, the 18th-site glutamic acid of wild-type formate dehydrogenase with an amino acid sequence shown as SEQ ID NO.2 is mutated into proline, the 57th-site asparagine is mutated into glutamic acid, the 70th-site histidine is mutated into tryptophan, the 235th-site serine is mutated into threonine, and the 316th-site valine is mutated into threonine, so that the formate dehydrogenase mutant is high in enzyme activity and catalytic activity; the coenzyme circulation efficiency during the production of D-mannitol can be obviously improved, so that the yield of D-mannitol can be effectively improved. When the genetically engineered bacterium co-expressed by the formate dehydrogenase mutant and the mannitol dehydrogenase mutant is used for catalyzing 150 g / L fructose to produce D-mannitol, the yield of D-mannitol within 15 h can reach 140 g / L or above.

The invention provides a fluorescent protein selection marker staygold-ygjHr gene and application thereof, and belongs to the technical field of biological engineering. The preparation method comprises the following steps: replacing codons of L-valine in nucleotide sequences of a fluorescent protein gene Staygold and a gene ygjH by using a rare codon GTC to respectively obtain a fluorescent protein gene Staygoldr after codon replacement and a gene ygjHr after codon replacement, and connecting the two segments of genes after codon replacement by using a flexible protein peptide to obtain the fluorescent protein selection marker Staygold-ygjHr gene. Experiments prove that the gene can obviously improve the screening efficiency of L-valine high-yield strains.

The invention provides a keto-alcohol acid reductoisomerase mutant and application of the keto-alcohol acid reductoisomerase mutant in construction of genetically engineered bacteria for high yield of D-pantothenic acid. In order to solve the technical problem that in the prior art, the yield of D-pantothenic acid synthesized through microbial fermentation is not high, semi-rational design of enzyme is adopted, and a keto-alcohol acid reductoisomerase mutant with substrate specificity is obtained and applied to construction of genetically engineered bacteria for high yield of D-pantothenic acid. According to the invention, a genetically engineered bacterium with high yield of D-pantothenic acid is constructed by utilizing the keto-alcohol acid reductoisomerase mutant through a CRISPR-Cas9 gene editing technology, so that the yield of D-pantothenic acid is increased by about 12.04%, and compared with an original strain, the valine accumulation amount in obtained fermentation liquor is almost unchanged compared with that of a control, and the yield of D-pantothenic acid is greatly improved. However, the accumulation of branched chain amino acid isoleucine is less, so that the modification of the substrate specificity of the keto-alcohol acid reductoisomerase is achieved.

The invention relates to the technical field of gene engineering and enzyme engineering, in particular to an esterase mutant for degrading ethyl carbamate and application of the esterase mutant, the esterase mutant has an amino acid sequence as shown in SEQ ID NO.1 which is subjected to site mutation, the site mutation is any one or more site combined mutation of V129S, V161L or I229M, and the amino acid sequence of the esterase mutant is shown in SEQ ID NO.1. The V129S site mutation is that valine at the 129 site is mutated into serine, the V161L site mutation is that valine at the 161 site is mutated into leucine, and the I229M site mutation is that isoleucine at the 229 site is mutated into methionine. Mutation is carried out through a site-directed mutagenesis method, so that the amino acid sequence of the esterase mutant V129S / I229M is changed, the autoplasmic structure and function of eggs are changed, the esterase mutant V129S / I229M with the ethyl carbamate hydrolysis rate increased to 6.55 times in an acid environment is finally obtained, and the esterase mutant V129S / I229M has high industrial application value.

The invention discloses a cyclic nonapeptide with repairing and anti-oxidation effects and application of the cyclic nonapeptide, the amino acid sequence of the cyclic nonapeptide is cyclic (arginine-glycine-aspartic acid-serine-arginine-lysine-valine-lysine-serine), the prepared cyclic nonapeptide has the repairing and anti-oxidation effects, and the cyclic nonapeptide has the repairing and anti-oxidation effects. The composition can be applied to preparation of cosmetics with repairing and / or anti-oxidation effects.

The invention discloses a hydrogel patch for gastric perforation repair and a preparation method thereof, and belongs to the technical field of biomedical materials. The preparation method comprises the following steps: dissolving acryloyl valine, acrylic acid, methylene bisacrylamide, a compound A and a photoinitiator in an alcohol solvent, and defoaming to obtain a precursor solution; and placing the precursor solution in a mold, carrying out ultraviolet-induced curing, soaking the obtained hydrogel in a hydrochloric acid solution, and replacing the alcohol solvent to obtain the hydrogel patch for gastric perforation repair. The hydrogel patch provided by the invention has the advantages of strong acid corrosion resistance, good biocompatibility, low swelling ratio, stable adhesion performance in a fluctuating pH environment and the like. The tough and stable adhesion performance ensures that the hydrogel can be permanently and reliably adhered to a gastric perforation part in a dynamic gastric acid environment, and a stable platform is provided for drug delivery, so that the surgical operation time is expected to be shortened, and wound healing is promoted.

The invention relates to an L-valine production strain as well as a construction method and application thereof, the strain is obtained by transformation through a metabolic synthesis path of L-valine, and the construction method comprises the following steps: by taking Cornebacterium glutamicum ATCC 13032 (C.glutamicum) as an original strain, carrying out editing transformation such as gene knockout, gene overexpression, gene heterologous expression, gene double-copy expression and the like on a genome of the original strain by utilizing a metabolic engineering means. The L-valine production strain disclosed by the invention can be used for synthesizing L-valine from the beginning by taking glucose as a carbon source, has the advantages of high production rate, short fermentation period, high strain stability and low cost, and lays a foundation for realizing large-scale production of L-valine. According to the fermentation tank fermentation method, the L-valine is produced in a mechanical stirring type fermentation tank by using the L-valine production strain Va1-09, 86.4 g / L of L-valine is produced by fermenting for 36 hours, and the method has a good industrial prospect.

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 a branched chain amino acid transaminase gene and application thereof, and belongs to the field of gene engineering. According to the invention, the branched chain amino acid transaminase gene HvBCAT5 is found for the first time, and the gene has obvious positive correlation with the accumulation of valine (Val), isoleucine (Ile) and leucine (Leu) of crops. The invention provides an important target gene HvBCAT5 for crop quality improvement, and has important value for increasing the content of branched chain amino acid of crops and improving dietary nutrition. The HvBCAT5 gene as well as a recombinant vector, a recombinant bacterium and a transgenic plant thereof have good application prospects in the fields of food and feed industry.

The invention provides a keto-alcohol acid reductoisomerase mutant and application of the keto-alcohol acid reductoisomerase mutant in construction of genetically engineered bacteria for high yield of D-pantothenic acid. In order to solve the technical problem that in the prior art, the yield of D-pantothenic acid synthesized through microbial fermentation is not high, semi-rational design of enzyme is adopted, and a keto-alcohol acid reductoisomerase mutant with substrate specificity is obtained and applied to construction of genetically engineered bacteria for high yield of D-pantothenic acid. According to the invention, a genetically engineered bacterium with high yield of D-pantothenic acid is constructed by utilizing the keto-alcohol acid reductoisomerase mutant through a CRISPR-Cas9 gene editing technology, so that the yield of D-pantothenic acid is increased by about 12.04%, and compared with an original strain, the valine accumulation amount in obtained fermentation liquor is almost unchanged compared with that of a control, and the yield of D-pantothenic acid is greatly improved. However, the accumulation of branched chain amino acid isoleucine is less, so that the modification of the substrate specificity of the keto-alcohol acid reductoisomerase is achieved.

The present application relates to ketol reductoisomerase variants, polynucleotides encoding the variants of the present disclosure, L-valine-producing microorganisms comprising the ketol reductoisomerase variants of the present disclosure or the polynucleotides encoding the variants, and methods of producing L-valine using the microorganisms of the present disclosure.

The invention relates to the technical field of biology, and discloses a carbonyl reductase mutant and application thereof in enzymatic synthesis of chiral alcohol. The amino acid sequence as shown in SEQ ID NO.2 is subjected to mutation that 36th lysine is mutated into any one of aspartic acid, threonine and valine, or / and 125th histidine is mutated into any one of lysine, serine and leucine, or 170th histidine is mutated into any one of lysine, cysteine and leucine. The carbonyl reductase mutants, especially single-site mutants Mut-T75K, Mut-T75D and Mut-E216M and a combined mutant Mut-T75K-E216M, with activity improved to different extents compared with that of a wild type are obtained, have excellent relative enzyme activity, thermal stability and substrate tolerance, have relatively high activity and stability for various chiral alcohols, and can be used for preparing the carbonyl reductase mutants. The catalyst has the advantages of high catalytic activity, high thermal stability, strong substrate tolerance, easiness in fermentation and the like.

The invention discloses intestinal bacteria and serum metabolites which can be used as biomarkers of type 2 diabetes mellitus (prediabetes mellitus (PDM), new diagnosis diabetes mellitus (NDDM) and diabetes mellitus (P2DM) after medication) in different disease stages, and application of the intestinal bacteria and the serum metabolites. Aiming at type 2 diabetes mellitus, predictive markers including staphylococcus aureus, escherichia coli, klebsiella pneumoniae, branched chain amino acids (leucine, valine and isoleucine) and the like, especially staphylococcus aureus of which the genome contains acetolactate synthase (ALS), are efficiently screened out. The type 2 diabetes mellitus marker disclosed by the invention can be used for early warning the illness risk of type 2 diabetes mellitus and guiding the adjustment of an intestinal microbial environment; the method can be used for indicating the correlation between the intestinal microbial environment and the type 2 diabetes mellitus and is used for assisting diagnosis; and drug action target research, accurate medication, pathogenesis research and the like are realized.

The present invention discloses a pectin methylesterase mutant ΔDdPemA, its encoding gene, preparation method, and application. The pectin methylesterase mutant ΔDdPemA is obtained by mutating the amino acid at position 200 in the center of the substrate binding pocket of the wild-type pectin methylesterase DdPemA from a high-molecular-weight, branched valine to a low-molecular-weight alanine, and by mutating the amino acid at position 339 at the substrate inlet and outlet of the substrate binding pocket from a high-molecular-weight, branched valine to a basic lysine. The amino acid sequence and nucleotide sequence of the wild-type pectin methylesterase DdPemA are SEQ ID NO. 1 and SEQ ID NO. 2, respectively. The mutant enzyme provided by the present invention has significantly improved enzyme activity under weakly acidic conditions, solving the problem of insufficient catalytic activity of the wild-type pectin methylesterase under weakly acidic conditions and creating favorable conditions for the application of the enzyme in the fields of food, textiles, and feed processing.

The invention relates to the technical field of information, and discloses a method for predicting the optimal branched chain amino acid ratio of daily ration of lactating sows, which comprises the following steps of: 1, acquiring production data and feed formula data; 2, processing the production data and the feed formula data to obtain production sample data and formula sample data; 3, performing correlation calculation on the production sample data and the formula sample data to obtain most effective features and calculate feature vectors; 4, training a preset model according to the feature vector and the formula sample data; 5, verifying the preset model, and selecting an optimal prediction model according to an evaluation result; and 6, outputting an isoleucine content prediction value, a leucine content prediction value and a valine content prediction value by the optimal prediction model. The prediction method can accurately and reliably predict the branched chain amino acid proportion of daily ration with different protein levels. Meanwhile, the invention further provides a prediction device for the optimal branched chain amino acid proportion of the daily ration of the lactating sow.

The invention relates to a mutant based on cytochrome P450BM3 and application of the mutant in chloroaniline biodegradation, and belongs to the field of enzymology. The mutant is obtained by mutating threonine at the 268 site of an amino acid sequence shown in SEQ ID NO.1 into aspartic acid or glutamic acid, mutating alanine at the 328 site into phenylalanine, and mutating alanine at the 328 site into phenylalanine. According to the present invention, the amino acid at the 87 site is mutated into alanine, and the valine at the 78 site is mutated into alanine, such that a variety of mutants such as T268D / A328F, T268E / A328F, T268D / A328F / F87A, T268E / A328F / F87A, T268D / A328F / F87A / V78A and T268E / A328F / F87A / V78A are obtained; according to the present invention, the degradation rate of the mutant on 4-chloroaniline, 2-chloroaniline, 2, 4-dichloroaniline, 3, 4-dichloroaniline and 3, 5-dichloroaniline is achieved; the method has important significance and application value for promoting rapid degradation of chloroaniline pollutants in a water environment and maintaining ecological balance.

The invention discloses escherichia coli recombinant bacteria with high glycolic acid yield and a construction method of the escherichia coli recombinant bacteria, and belongs to the technical field of bioengineering. Lactate dehydrogenase ldhA, phosphate transacetylase pta, acetokinase ackA and pyruvate oxidase poxB are knocked out in escherichia coli, key enzymes isocitrate lyase aceA and glyoxylate reductase ghrA in a glycollic acid synthesis path are over-expressed in a genome level, conversion of carbon flow to glycollic acid is enhanced, and the glycolic acid is converted into glycolic acid. On the basis, malic acid synthase AaceB, malic acid synthase GglcB and glycollic acid oxidase glcDEF are knocked out, a branch metabolic pathway is blocked, an efficient strain which is free of plasmids and resistance genes and does not need to induce glycollic acid production is constructed, the accumulation amount of L-valine fermented in a 5L fermentation tank for 48 hours reaches 51.2 g / L, the yield is 0.6 g / g, and the production intensity is 1.06 g / L / h.

The invention provides a nicotinamide nucleotide transhydrogenase mutant and application thereof, valine at the 169th site of the nicotinamide nucleotide transhydrogenase mutant is designed to be mutated into isoleucine, the isoleucine is used for constructing a lysine production strain, and the new strain does not contain plasmids, does not have growth defects, does not need induction, and has the advantages of good genetic stability, high fermentation yield and the like. The lysine can be efficiently and stably produced from the beginning by taking glucose as a substrate.

The invention provides a valine production strain and a construction method and application thereof, a designed acetohydroxy acid synthase mutant is that the 88th basic group of an ilvB gene is changed from a to c, the 382nd basic group is changed from a to g, the 413th basic group is changed from c to t, the gene sequence of a designed artificial operon comprises a promoter, an ilvB (A138V) gene or ilvB (Q30K, S128G, A138V) gene of coding mutated acetohydroxy acid synthase, and an ilvN (G20D, I21D, I21D, I21D, I21D, I21D, I21D, I21D) gene. I22F) gene, a pyk gene for coding pyruvate kinase, and a terminator; by designing a specific acetohydroxyacid synthase mutant and related biological materials and artificial operon, the strain constructed by directional modification of the strain by using a pK18mobsacB system gene editing technology based on allele exchange has the advantages of good genetic stability, high fermentation yield and the like, and valine can be stably produced.

The invention provides a nicotinamide phosphoribosyltransferase mutant and an application of the nicotinamide phosphoribosyltransferase mutant in preparation of beta-nicotinamide mononucleotide. According to the nicotinamide phosphoribosyltransferase mutant, 259th lysine (K) of an amino acid sequence shown in SEQ ID NO: 2 is mutated into 259th valine (V). The invention overcomes the technical problems of slow reaction, low yield, high energy consumption and NMN feedback inhibition of the product in the process of producing NMN by escherichia coli, and the constructed nicotinamide phosphoribosyltransferase mutant expression system is used for fermentation production of nicotinamide mononucleotide, and slows down the feedback inhibition effect.

The present invention relates to the field of bioengineering technology and provides a sucC mutant and its application in the fermentative production of L-valine. By performing point mutations on the sucC gene, the present invention reduces the enzyme expression activity, balances the metabolic flux problem between the TCA cycle for cell growth and product accumulation, and thus improves the valine yield. Further, through experimental screening, a recombinant strain capable of significantly increasing the valine yield is obtained. From the fermentation results, it can be seen that this method can significantly increase the valine yield, from the original 1.3 g / L to 1.61 g / L, with a 23.8% increase in yield, providing strong strain support for further industrialization.

The present application relates to a pyridoxal kinase mutant, a recombinant expression vector and a microbial cell and their applications, and belongs to the technical field of biological catalysis. In order to solve the problem of low product concentration in existing enzyme catalysis, a pyridoxal kinase mutant is provided, the amino acid sequence is selected from the amino acid sequence shown in SEQ ID NO. 1, the lysine at position 229 is mutated to alanine, phenylalanine, methionine, arginine, threonine, histidine, serine, tyrosine, valine, leucine, isoleucine, proline, asparagine, aspartic acid or glutamic acid; the pyridoxal kinase mutant is used for catalyzing pyridoxal to synthesize pyridoxal phosphate, and a recombinant expression vector and a microbial cell can be further formed. The present application has good enzyme activity, high product conversion rate, high concentration of pyridoxal phosphate obtained, and the concentration of the product catalyzed by the wild-type pyridoxal kinase to phosphorylate pyridoxal is obviously improved.

The invention provides an oligosaccharide debranching enzyme mutant and use thereof in a glucose mother liquor. The mutant is obtained by mutating valine at position 219 in SEQ ID NO: 1 into alanine. According to oligosaccharide debranching enzyme mutant V219A, a primary mother liquor, a secondary mother liquor, or a tail liquid after chromatographic separation is used as a substrate, the percentage contents of glucose in the products are 99.21% (primary mother liquor), 98.89% (secondary mother liquor) and 97.97% (tail liquid after chromatographic separation) respectively, which are 2.86%, 8.64%, and 28.67% higher than that of glucose obtained with the wild-type oligosaccharide debranching enzyme. Therefore, the mutant V219A obviously improves the percentage content of glucose in the glucose mother liquor, and the scope of application of the mother liquor can be expanded by the high product purity and substrate conversion rate, so the mutant V219A has higher industrial application value.

The invention discloses a mycobacterium tuberculosis tyrosine phenol lyase mutant and application thereof, and belongs to the field of molecular biology and the technical field of biological catalysis. The mutant is obtained by mutating 384 isoleucine of tyrosine phenol lyase from mycobacterium tuberculosis into valine, and is marked as a mutant I384V. The I384V and wild type tyrosine phenol lyase have similar optimum temperature and optimum pH, but the I384V shows higher specific enzyme activity and catalytic efficiency than the wild type tyrosine phenol lyase. Compared with a wild type, the tyrosine phenol lyase mutant I384V has the advantages that the synthesis efficiency of the tyrosine phenol lyase mutant I384V on the synthesis of levodopa is improved by 38.4%, and the tyrosine phenol lyase mutant I384V has wide prospects in large-scale industrial application.

The invention relates to the technical field of biology, and discloses a recombinant carbonyl reductase mutant and application thereof in synthesis of chiral alcohol. According to the invention, the 36th-site lysine is mutated into any one of aspartic acid, threonine and valine, or / and the 125th-site histidine is mutated into any one of lysine, serine and leucine, or / and the 170th-site histidine is mutated into any one of lysine, cysteine and leucine; the carbonyl reductase mutants, especially single-site mutants Mut-K36D and Mut-H125K and a combined mutant Mut-K36D-H125K, with activity improved to different extents compared with that of a wild type are obtained, have excellent thermal stability and relative enzyme activity, have relatively high activity and stability aiming at various chiral alcohols, and can be used for preparing the carbonyl reductase. The method has the advantages of high catalytic activity, high enzyme expression quantity, easiness in fermentation and the like.

Provided herein are self-assembling collagen-like peptide (CLP) comprising a plurality of amino acid trimer repeats having the amino acid sequence POG, wherein P is a proline, O is an hydroxyproline or a cysteine, and G is a glycine or a valine. Also provided herein are compositions, scaffolds, photoactivatable hydrogel precursors and hydrogels comprising the CLP and a multi-arm polyethylene glycol (PEG) polymer. Methods of preparing photoactivatable hydrogel precursors and hydrogels are also described. Methods of treating a wound, of treating a corneal disease, of treating a myocardial infarct, of promoting cell growth and of treating cellular degeneration using the compositions, scaffolds, photoactivatable hydrogel precursors and / or hydrogels are also described. Also provided is a device for delivering a peptide-based material. The device comprises an on / off button or switch for initiating and stopping delivery of the peptide-based material in the subject; a chamber for containing the peptide-based material; an aperture through which the peptide-based material exits the chamber, wherein the aperture is adapted for receiving a nozzle adapter; a camera port for securing a camera thereto; and a digital control display.

The present invention relates to the field of bioengineering technology and provides a ppc mutant and its application in the fermentative production of L-valine. By performing point mutations on the ppc gene, the expression activity of phosphoenolpyruvate carboxylase is reduced, the competition of the bypass pathway is weakened, the supply of pyruvate precursors is enhanced, and the production capacity and biomass of the valine engineering strain are further improved. It can be seen from the fermentation results that this method can significantly increase the yield of valine, from the original 1.3 g / L to 1.49 g / L, with a 14.6% increase in yield. Therefore, the present invention has application value.

The invention provides a valine production strain as well as a construction method and application thereof, the strain is constructed by utilizing a CRIPSR / Cas9 system gene editing technology based on allele exchange, an artificial operon is designed and constructed, the artificial operon is constructed at a ygaY site, a strong promoter Ptrc is used for controlling ilvIH (G14N S17F)-pykF to carry out synchronous multi-copy expression, and the valine production strain can be used for producing valine. On the basis of the strain, an artificial operon is constructed at an ycgH site, a strong promoter Ptrc is used for controlling ilvC-ilvD to carry out synchronous multi-copy expression, meanwhile, feedback inhibition of valine on ilvIH is relieved, and an ilvIH natural promoter is replaced by the strong promoter Ptrc, so that more pyruvic acid flows to valine; the constructed strain does not contain plasmids, has no defects, does not need induction, has the advantages of good genetic stability, high fermentation yield and the like, and can be used for efficiently synthesizing valine from the beginning by taking glucose as a substrate.

The present disclosure is directed to HLA class II molecules having a higher affinity for CD4 than naturally occurring HLA class II molecules. In certain aspects, the HLA class II molecule comprises a DQ beta chain having (i) an amino acid other than leucine at a position corresponding to amino acid residue 114 of SEQ ID NO: 1, (ii) an amino acid other than valine at a position corresponding to amino acid residue 143 of SEQ ID NO: 1, (iii) or both (i) and (ii). Certain aspects of the present disclosure are directed to nucleic acid molecules encoding the HLA class II molecules, vectors comprising the nucleic acid molecule, cells comprising the same, and methods of use thereof.