80 results about "Point mutant" patented technology

The invention provides a system for efficient multi-point interposition of unnatural amino acid into mammalian cells. The system comprises an expression vector for expressing protein containing unnatural amino acid, wherein the unnatural amino acid is encoded by a codon UAG and contains a vector of methanogen tRNA (tRNAPyl) and pyrrolysyl-tRNA synthetase (PylRS); and the system also comprises an eRF1 cell line obtained from mutation. In addition, the invention also provides a method for preparing fixed-point mutant protein with the application of the system.

The present invention provides a recombinant PAI-1 inhibitor, which is an uPA hydrolase domain with S195A mutation or a PAI-1 hydrolase domain with S195A mutation, and has PAI-1 binding force. The present invention further provides a composition containing the inhibitor, and uses of the composition in preparation of treatment drugs and PAI-1 detection reagents. According to the present invention, the uPA or tPA hydrolase domain is modified to optimize the binding force with the PAI-1 so as to construct the recombinant PAI-1 inhibitor, wherein the recombinant PAI-1 inhibitor contains the least S195A point mutant.

The invention relates to the method of gene fixed-point mutation which is a modified overlap extension PCR method and the mutated gene. The process includes the fragment composition, the double mixing, the prepared extension, the whole DNA composition and after extension. The method is detected by the synzyme gene sam1 from the SAM of the Saccharomyces cerevisiae and gets the mutated gene modified by the rare coden. The SAM synzyme encoding by the gene can express in the yeast and improves the yield of the intracellular SAM. The invention can reach the many fixed-point mutations in a same reaction process.

The invention relates to the technical field of molecular biology, and particularly discloses a sarcoma fusion gene joint detection primer group, kit and detection method. The kit provided by the invention comprises: 1) a special linker for DNA library construction; 2) a specific composite primer for detecting fusion genes and point mutation; and 3) a composite primer for library amplification. DNA and RNA of a to-be-detected sample are respectively extracted, reverse transcription is performed on RNA to synthesize cDNA, the cDNA is mixed with DNA, fragmentation, terminal repair and linker ligation are performed on the mixture, PCR amplification is performed on the product, a library is enriched, and high-throughput sequencing is performed. According to the fusion gene detection kit and detection method provided by the invention, various fusion genes or mutations related to sarcoma can be detected at one time, the detection efficiency is improved, the operation is convenient, the consumption time is short, and the sensitivity is relatively high and can reach 0.1%.

This invention relates to novel nonmammalian carrier vectors and viruses useful in the production of high titers of recombinant viruses which may contain foreign DNA inserts or which may be point-mutated or deleted viruses, and methods of producing those viruses. The nonmammalian carrier vector (“carrier vector”) is a chimeric vector which includes those portions of a nonmammalian virus backbone which allow replication in a nonmammalian host cell. The carrier vector includes various nucleic acid cassettes, which may include an embedded recombinant viral genome containing a desired transgene, components necessary for production of a replication-defective recombinant virus containing the transgene, and domains that permit the carrier vector to bind to mammalian cells. The invention also provides methods of producing high concentrations of recombinant virus as a substantially homogeneous. preparation, compositions to produce the recombinant virus, and novel recombinant viruses.

The invention discloses cyclodextrin glycosyl transferase with improved maltodextrin substrate specificity and a preparation method thereof, and belongs to the field of genetic engineering and enzyme engineering. 195-bit tyrosine (Tyr) of CGTase of P.macerans strain JFB05-01 (CCTCC NO:M208063) is replaced by serine (Ser), 260-bit tyrosine (Tyr) is replaced by arginine (Arg), and 265-bit glutamine (Gln) is replaced by lysine (Lys), so that the AA-2G yield is respectively improved by 23 percent, 44 percent and 40 percent. According to combined mutation of the mutant strains, double mutants Y195S/Y260R, Y195S/Q265K and Y260R/Q265K and A three-point mutant Y195S/Y260R/Q265K are obtained. A Glycosyl donor is produced by the maltodextrin, so that the AA-2G yield is respectively improved by 57 percent, 49 percent, 55 percent and 59 percent; and compared with the mild type CGTase, the mutant strains facilitate the production of the AA-2G for glycosyl donors by using maltodextrin.

The invention discloses a cyclodextrin glycosyl transferase with improved maltodextrin substrate specificity and a preparation method thereof and belongs to the fields of genetic engineering and enzyme engineering. According to the invention, for CGTase derived from peanibacillus macerans, lysine at a 47th site, tyrosine at a 89th site, asparaginate at a 94th site and aspartic acid at a 196th site are respectively mutated into leucine K47L, phenylalanine Y89F, praline N94P and tyrosine D196Y, so that AA-2G yields are respectively increased by 30.7%, 10.9%, 10.0% and 31.7%. Complex mutation is carried out on the mutant strains to obtain double mutants namely K47L/Y89F, K47L/N94P, K47L/D196Y, Y89F/N94P, Y89F/D196Y and N94P/D196Y, three-point mutants namely K47L/Y89F/N94P, K47L/Y89F/D196Y, K47L/N94P/D196Y and Y89F/N94P/D196Y and a four-point mutant namely K47L/Y89F/N94P/D196Y. Yields of AA-2G produced by the mutants while maltodextrin is utilized as a glycosyl donor are respectively increased by 42.6%, 11.0%, 37.6%, 43.6%, 43.6%, 41.6%, 44.5%, 50.5%, 20.8%, 35.6% and 64.4%. Compared with the wild type CGTase, the mutants is more beneficial to production of the AA-2G while the maltodextrin is utilized as the glycosyl donor.

The invention discloses a cephalosporin C acylase mutant with a high thermal stability constructed by point mutation, which has an amino acid sequence selected from SEQ ID Nos: 3-7. Compared with initial cephalosporin C acylase with SEQ ID No: 1, the cephalosporin C acylase mutant disclosed by the invention has high thermal stability and higher enzyme activity, so that the cephalosporin C acylasemutant can be used for producing 7-aminocephalosporanic acid by adopting an one-step enzymatic method.

The invention discloses a type of polyethylene glycol erythropoietin, which is prepared from non-glycosylated rhEPO(rhngEPO) or point mutant thereof, and N-terminal amino of single and single chain PEG molecule having molecular weight greater than 20kDa or mercapto of cysteine mutational state by fixed point coupling, wherein the olyethylene glycol erythropoietin has the molecular structural formula of CH3-(CH2CH2-O)n-(CH2)r-NH-rhngEPO or CH3-(CH2CH2-O)n-X-S-rhngEPOm, wherein n is 100 to 2,200, r is 0 to 4, and X is S or C. The PEG-rhngEPO or PEG-rhEPOm molecule simultaneously has long-acting preparation characteristics such as long acting, high efficiency and low immunogenicity, and establishes foundation for preparing parent long-acting preparation for treating anemia caused by chronic renal insufficiency, tumor, anemia caused by AIDS chemotherapy, marrow brain nerve damage, and selective operation auto-transfusion.

The invention relates to a lovastatin acyltransferase mutant. The mutant contains an acyltransferase amino acid sequence represented by SEQIDNO.1 of wild A. terreus and at least 2-6 amino acid mutations selected from N45R, A110P, S145N, Q230M, L293M and L379M. The invention also relates to a nucleic acid nucleic acid for coding the mutant, a relevant expression vector, a host cell, and a use of the mutant in the synthesis of lovastatin.

The invention relates to the technical field of molecular biology, and particularly discloses a plasma free DNA lung cancer fusion gene combined detection primer group and kit. The kit provided by theinvention comprises: 1) a special linker for DNA library construction; 2) a specific composite primer for detecting fusion genes and point mutation; and 3) a composite primer for library amplification. According to the detection kit, DNA of a sample to be detected is extracted and subjected to fragmentation, terminal repair and linker connection, a product is subjected to PCR amplification, and high-throughput sequencing is performed after library enrichment. According to the fusion gene detection kit and detection method provided by the invention, various fusion genes or mutations related tolung cancer can be detected at one time, the detection efficiency is improved, the operation is convenient, the consumption time is short, and the sensitivity is relatively high and can reach 0.0625%.

The present invention relates to the provision of the genetic sequence of the major grass pollen allergen Phl p 4. The invention also covers fragments, new combinations of partial sequences and point mutants having a hypoallergenic action. The recombinant DNA molecules and the derived polypeptides, fragments, new combinations of partial sequences and variants can be utilised for the therapy of pollen-allergic diseases. The proteins prepared by recombinant methods can be employed for the in vitro and in vivo diagnosis of pollen allergies.

The invention discloses an EstWY enzyme mutant having improved activity, and belongs to the technical field of enzyme engineering. An EstWY enzyme sequence is analyzed by using a consensus method without phylogenetic prejudice to obtain single-point mutants having remarkably improved activity through screening, and site-specific mutagenesis is performed on the single-point mutants to obtain mutantY179E/V190D, T196R/L202H and V190D/A193H/T196R enzymes having improved activity, which are 3 times higher than wild enzymes. The EstWY enzyme mutant provided by the invention is better in activity and shows excellent catalytic activity when creatine is catalyzed to generate fatty acids and alcohols at a relatively high temperature, besides, the constructed EstWY enzyme genetically engineered bacterium can efficiently express the EstWY enzyme mutant, and the EstWY enzyme genetically engineered bacterium has the advantages of simple culture conditions, short culture period, convenience in purification of expression products and the like.

The invention discloses a variant of Kex2 enzyme and a stable expression method, the variant is formed by properly truncating a Kex2 amino acid sequence and performing point mutation, the variant canstably and efficiently secrete and express a target protein through a constitutive pichia pastoris expression system, and good biological enzyme activity is maintained. The fermentation process is simple, efficient, low in cost, high in product activity and suitable for commercial production.

The invention aims to provide a heat-resistant glucose oxidase mutant. Remained enzyme activity is 29.02% and remarkably higher than that of a wild type after the glucose oxidase mutant containing V104I single-site mutation is processed for 2.5 minutes at the temperature of 70 DEG C. In order to further improve heat resistance of a glucose oxidase three-point mutant GOD-K (A65R, H275F and A416K),V104I single-site mutation and combination of mutation sites of V104I and T32L and/or A290L are introduced, and results display that the heat resistance of an acquired mutant is remarkably higher thanthat of the GOD-K, and the remaining enzymatic activity of the mutant reaches up to 83.10% after acquired mutant is processed for 2.5 minutes at the temperature of 75 DEG C and is improved by 46.42%as compared with that of the GOD-K, so that the mutant is more suitable for the field of feed processing.

The invention discloses a recombinant adeno-associated viral vector with HPV-16 (human papillomavirus-16) E7<mm> antigen genes and a method for constructing the recombinant adeno-associated viral vector. The method includes mutating tumorigenicity HPV-16 E7 antigen genes at multiple points to obtain non-tumorigenicity E7 antigen genes; inserting the mutated genes into an adeno-associated viral vector without structural genes to obtain the recombinant adeno-associated viral vector. The recombinant adeno-associated viral vector and the method have the advantages that the mutant HPV-16 E7<mm> antigen genes carried by recombinant adeno-associated viruses can be delivered into monocyte-dendritic cell lines to be used for stimulating effect cells of immune systems; as proved by experiments, growth of HPV-16 E7 positive cells can be effectively inhibited by CTL (cytotoxic lymphocytes) induced by DC (dendritic cells) infected by the recombinant adeno-associated viruses for patients in in-vitro and in-vivo manners, or the HPV-16 E7 positive cells can be effectively killed by the CTL for the patients in the in-vitro and in-vivo manner, and tumorigenicity can be prevented; the recombinant adeno-associated viral vector or associated products can be used for preparing anti-tumor medicine for treating HPV-16 infection or diseases associated with the HPV-16 infection.

The invention relates to the technical field of gene detection, in particular to a fluorescent PCR detection method for simultaneously detecting deletion mutation and point mutation of genes by a single tube. The method comprises the following steps: screening out available primers and probes, wherein the Tm value of the primers is higher than that of the probes; performing PCR reaction in the same reaction system of the single tube by using the obtained primers and probes; detecting change of the fluorescence value of the PCR reaction by using an instrument, analyzing and acquiring a channelfluorescence signal corresponding to the designed probe, and judging whether a detected sample has certain deletion mutation or not according to existence of melting peaks of all fluorescence channels; judging whether the detected sample has certain point mutation or not according to the temperatures of the melting peaks of all the fluorescence channels. The method has the beneficial effects thata plurality of deletion mutations and a plurality of point mutations can be simultaneously detected by only adding genome DNA of the detected sample into a detection reagent, one-time closed tube operation is realized, and pollution of a PCR product to an experimental environment is eliminated.

The invention particularly relates to a Heg1 gene point mutation mouse model as well as a construction method and application thereof. The construction method comprises the following steps: S1, constructing a targeting vector knocked in by Heg1 gene point mutation; s2, after plasmid extraction and linearization, a targeting vector is transfected to ES cells; s3, screening and identifying the positive ES cells to obtain positive clones of correct homologous recombination, and injecting the cloned positive ES cells into the blastocysts of the donor mice to obtain chimeric mice; s4, mating the chimeric mouse with the Flp mouse to obtain an F1-generation mouse, and screening to obtain an F1-generation heterozygote mouse in which Neo in the targeting vector is removed; s5, selfing the F1-generation heterozygote mice to obtain F2-generation mice, and screening to obtain recessive pure mutant mice, namely the Heg1 gene point mutation mouse model. The technical scheme provided by the embodiment of the invention can be applied to research and development of related prevention, treatment or diagnosis medicines for the premature cranial closure syndrome, and has important significance in the aspects of premature cranial closure surgery, pathogenesis of congenital heart disease treatment, treatment methods, medicine screening and the like.