119 results about "Double mutant" patented technology

The invention relates to the field of gene engineering and particularly discloses a tool for efficient site-specific transposition of genes. The tool comprises or can produce a gRNA-Cas9 protein (without incision enzyme activity)-PB transposase compound, and gRNA targets the specific site of a genome; the Cas9 protein without incision enzyme activity is double-mutant Cas9 protein with 10th-site amino acid residue D mutating into A and 840th-site amino acid residue H mutating into A. Through design of gRNA (guide RNA) targeting the animal genome, under the coexpression condition of gRNA and site-specific transposase, PB transposase is targeted to a specific position of the genome along with a CRISPR/cas9 and gRNA compound, the PB transposase realizes a transposition function at the specific site, accordingly, donor plasmids (carriers containing exogenous target genes) are simultaneously co-transfected, the exogenous target carriers can be transposed to the specific site in the genome through transposition, and site-specific transposition of the genes is realized.

The invention includes auxotrophic attenuated mutants of Listeria and methods of their use as vaccines.

The present invention provides RecA mutant proteins, having either a single mutation or a double mutation. The RecA mutant proteins are highly proficient in both SSB displacement and steady state binding of DNA in the presence or absence of SSB as compared to the wild-type protein. The single RecA mutant, RecAΔC17, has 17 amino acid residues removed from the carboxyl terminus. The double mutant RecA, RecAΔC17/E38K, combines the 17 amino acid residue C-terminal deletion of RecAΔC17, with a single amino acid change from Glutamate to Lysine at position 38. These RecA mutant proteins are pH sensitive allowing control over formation of products. Hence, methods of using the novel RecA mutants and kits having the RecA mutants as components thereof are also contemplated by the present invention.

The invention discloses a pyrimidine compound, an EGFR inhibitor and application of the EGFR inhibitor. The pyrimidine compound is prepared from a compound shown in the formula I or pharmaceutically acceptable salt thereof, a stereoisomer, and a solvate or prodrug. The EGFR inhibitor contains the pyrimidine compound. The pyrimidine compound can inhibit activated or resistant mutation of one or more kinds of EGFRs, can inhibit proliferation of the EGFR T790M/L858R double-mutant enzyme in the nanomolar concentration, but has a weak inhibiting effect on the wild EGFR enzyme; the pyrimidine compound is applicable to treatment of the EGFR-sensitive mutations cancer and also suitable for cases with secondary dug resistance in present EGFR-TKI treatment; meanwhile, toxic and side effects caused by inhibition on the wild EGFR are greatly reduced due to the mutation selectivity of the pyrimidine compound, and the pyrimidine compound is an ideal treatment drug for diseases caused by EGFR mutation.

It has been discovered that β-L-2′-deoxynucleosides are active against drug-resistant hepatitis B virus with mutations. A method for treating lamivudine resistant HBV (M552V) in a host is provided that includes administering a β-L-2′-deoxynucleoside or its pharmaceutically acceptable salt, ester or prodrug. In addition, a method for preventing lamivudine resistant HBV (M552V) mutation from occurring in a naïve host is provided that includes administering a β-L-2′-deoxynucleoside or its pharmaceutically acceptable salt, ester or prodrug. A method for preventing and/or suppressing the emergence of the HBV double mutant (L528M/M552V) in a host is also provided that includes administering a β-L-2′-deoxynucleoside or its pharmaceutically acceptable salt, ester or prodrug.

The invention discloses KASP marker primers for detecting simultaneous SNP mutations in Ser627Asn and Val643Met of rice ALS genes. In terms of the simultaneously generated SNP mutations in the Ser627Asn and the Val643Met of the rice ALS genes, when the phenotype of the double mutant ALS genes is labeled, the sequence of the double mutant ALS genes is a new unreported gene sequence which can primarily determine the labeled material, and then accurately determine the labeled rice material throughdouble KASP markers in the genes so as to carry out quick, highly accurate and high-throughput identification of anti-acetyl lactate synthase inhibitor herbicides of the rice. When the KASP marker primers are used for molecular marker-assisted breeding of hybrid rice varieties with herbicide resistance, the results of two pairs of KASP markers are validated mutually in order to effectively remove sterile line seedlings obtained via 'Tako' selfing by spraying herbicides.

The present invention discloses a recombinant soluble FGFR2 extracellular domain and the production method as well s the application of the extracellular domain. The present invention is based on the high-efficient expression FGFR2 of escherichia coli. Qualitative and quantitative researches have done concerning a plurality of factors that affect the renaturing efficiency. A proper method for recombinant soluble FGFR2 extracellular domain is determined. The renaturing efficiency can be of 10 percent to 20 percent. The present invention is of low cost and short cycle. The present invention is suitable for mass production. And the present invention takes advantage of the combination of dissociative extracellular domain of FGFRs with the FGFs in the tumor tissue to reduce the amount of dissociative FGFs, competitively leading to the repressive FGFs signals and the restraining proliferation and transfer of tumor as well as the depressed formation of blood vessels. S252W+P253R extracellular domain and double-mutant FGFR2 extracellular domain are of the best efficiency.

Duchenne muscular dystrophy (DMD) is a progressive muscle disease that is caused by severe defects in the dystrophin gene and results in the patient's death by the third decade. The present invention utilizes the Double Mutant mice (DM) as an appropriate human model for DMD as these mice are deficient for both dystrophin and utrophin (mdx/+, utrn −/−), die at 3 months of age and suffer from severe muscle weakness, pronounced growth retardation, kyphosis, weight loss, slack posture, and immobility. Expression from a transgene of novel human retinal dystrophin Dp260 was shown to prevent premature death and reduce the severe muscular dystrophy phenotype to a mild clinical myopathy. Electromyography, histology, radiography, magnetic resonance imaging, and behavior studies concluded that DM transgenic mice grew normally, had normal spinal curvature and mobility, and had reduced muscle pathology. EMG and histologic data from transgenic DM mice showed decreased abnormalities to levels typical of mild myopathy, while the DM mice exhibited severe abnormalities commonly seen in human dystrophinopathies. The transgenic DM mice also had measurable movement levels comparable to those of untreated mdx mice and controls.

The invention discloses a high-thermal-stability mutant of D-allulose-3-epimerase and an application of the high-thermal-stability mutant of D-allulose-3-epimerase. The 116th bits of serine of the mutant at D-allulose-3-epimerase is mutated to isoleucine, and the 251st bits of lysine is mutated to leucine, and a double mutant enzyme S116I/K251L is obtained. According to the invention, the 116th bit of serine (Ser, S) of D-allulose-3-epimerase BsDPE of Burkholderia sp. MR1 is mutated to isoleucine (Ile, I), and the 251st bits of lysine (Lys, K) is mutated to leucine (Leu, L), thus the thermal stability of the double mutant enzyme S116I/K251L obtained therefrom is significantly improved; and the half-life period at 60 DEG C is improved from the wild type 337.3 min to 417.9 min at present, and is 1.24 times o the wild type; the using cycle of the enzyme in compounding D-allulose is largely prolonged; the high-thermal-stability mutant of D-allulose-3-epimerase has important industrial application value.

The invention relates to a mutant of a cyclodextrin glucosyltransferase with the capability of highly yielding alpha-cyclodextrin and a mutation method, which belong to the fields of gene engineering and enzyme engineering. The invention improves the specificity of products of the cyclodextrin glucosyltransferase (CGT enzyme for short), provides a mutant proposal for improving the capability of CGT enzyme from Peanibacillus macerans JFB05-01 (CCTCC NO: M 208063) for producing the alpha-cyclodextrin, and substitutes Asp on the 372 position of the CGT enzyme for Lys, and Tyr on the 89 position as Asp and Arg to respectively obtain single mutant enzyme D372K, Y89D and Y89R; the alpha-cyclodextrin production capacity of the obtained mutant enzyme is improved compared with wild type CGT enzymes; genetic fragments of the CGT enzyme with Lys 372 are substituted by corresponding genetic fragments of Y89R so as to obtain double mutant enzyme D372K/Y89R; and the yield of the alpha-cyclodextrin of the ouble mutant enzyme D372K/Y89R is improved by 1.5 times compared with the wild type CGT enzyme, while the yield of the beta-cyclodextrin is reduced by 57 percent. The mutants are more favorable for industrial production of the beta-cyclodextrin than the wild type CGT enzymes.

The invention discloses target specific double mutant fusion protein, which is established by human gonadotropin releasing hormone mutant (mGnRH) and recombinant pseudomonas aeruginosa exotoxin A mutant (PE38m4a) fusion protein. The mGnRH-PE38m4a protein provided by the invention has obvious specific binding activity and cytotoxicity to the tumor cell lines which comprise colon cancer HT-29 cells, oophoroma OVCAR3 cells, cervical adenocarcinoma HeLa cells or liver cancer HepG-2 cells, and the like; the normal cells basically have no lethal function; the activity of the fusion protein is enhanced by approximate nine to ten times compared with the activity of natural PEA; the cost is low, the method is simple, therefore the target specific double mutant fusion protein is more suitable for industrialized production.

The present invention pertains to Bordetella bacteria having a double mutation, a first mutation in a gene of the Type III secretion system and a second mutation in a gene of the adenylate cyclase toxin (CyaA) locus of the bacteria so that the mutations result in no Type III secretion system, a non-functional Type III secretion system, no CyaA protein, or a non-functional CyaA protein or a combination thereof. The Bordetella bacteria double mutant is attenuated while maintaining the efficacy of the bacteria to elicit an immune response. The present invention also pertains to vaccine compositions and methods for treating and immunizing a mammal against a disease caused by infection of Bordetella bacteria or a disease caused by a pathogen.

The present invention relates to novel engineered Ga proteins and assay methods of using such proteins to advance drug discovery. Engineered Ga proteins described by the invention contain alterations of at least one and preferably two or more amino acid residues that are highly conserved among all four subfamilies of Ga proteins. A preferred engineered protein disclosed here is a double mutant, Gαπ R178M A326S. This specific combination of mutations yields an unexpectedly amplified effect on Ga function both in terms of GTPase activity (GTP hydrolysis) and GDP dissociation. This synergistic effect may have a profound influence on the way GPCR signaling pathways are examined for the development of new pharmacotherapies, particularly in the field of central nervous system disorders such as Parkinson's disease.

The present invention is directed to a cell line capable of supporting replication of a growth-defective Herpes Simplex Virus strain; specifically a replication-defective HSV-2 double mutant. Particularly disclosed is a cell line that expresses the ICP8 protein and the UL5 protein of Herpes Simplex Virus. This cell line is useful to propagate a replication-defective HSV-2 vaccine strain that contains mutations and/or deletions in the ICP8 and UL5 genes.

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 genetically engineered bacterium for expressing heat resistant type dextransucrase, as well as a construction method and application of the genetically engineered bacterium. The genetically engineered bacterium for expressing the heat resistant type dextransucrase is constructed as follows: a dex-YG gene obtained by cloning is inserted into an expression vector pET28(+)a, so as to obtain a recombinant expression plasmid pET28(+)/dex-YG which is taken as a template; site-directed mutagenesis is performed on a 473-site and a 856-site, heat-resistant double-mutants P473S/P856S with high enzyme activity is obtained after screening, and a recombinant engineered bacterium dex-YG-thMu01 is obtained from the conversion of a host bacterium E.ColiBL21(DE3). The genetically engineered bacterium dex-YG-thMu01 disclosed by the invention have the characteristics of heat resistance and high enzyme activity, and provide a certain basis for application of the genetically engineered bacterium dex-YG-thMu01 to industrial production of the dextransucrase; the productive capital can be saved.

The invention relates to the use of an antigen which is a non-toxic double mutant form of pertussis toxin for the manufacture of a vaccine composition for intranasal administration to induce an immune response against B. pertussis infection. The invention also relates to the use of a non-toxic double mutant form of pertussis toxin for the manufacture of an adjuvant composition for stimulating or enhancing a protective immune response of an antigen co-administered therewith. The non-toxic double mutant is preferably one in which the glutamic acid 129 amino acid in the S₁ sub-unit has been substituted by glycine and the arginine 9 amino acid has been substituted by lysine.

The invention discloses an EGFR (epidermal growth factor receptor) inhibitor for targeted therapy of cancers, and a preparation method and application thereof. The structural formula of the EGFR inhibitor is disclosed as Formula I, wherein R is H, OH, NR', C1-C3 alkyl, C1-C3 alkenyl, aryl or heterocycle, and R' is C1-C3 alkyl. The EGFR inhibitor can be used for preventing and/or treating cancers, such as human skin squamous carcinoma or lung cancer. Compared with the existing inhibitors (such as AZD9291, afatinib and the like), the EGFR inhibitor disclosed by the invention has novel chemical structure. The EGFR inhibitor can selectively inhibit cell lines of EGFR double mutants (EGFRT790M/L858R), and has lower inhibition activities for EGFR wild type cells. Therefore, the EGFR inhibitor disclosed by the invention can be used for treating the patient with lung cancer with EGFRT790M/L858R mutants, and has lower side effect (caused by the inhibition of the wild type EGFR, such as afatinib).

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 present invention provides a non-naturally occurring seed plant that is characterized by delayed seed dispersal due to ectopic expression of a nucleic acid molecule encoding an AGL8-like gene product. Further provided herein is a non-naturally occurring seed plant, such as an agl1 agl5 double mutant, that is characterized by delayed seed dispersal due to suppression of AGL1 and AGL5 expression in the seed plant. The invention also provides a substantially purified dehiscence zone-selective regulatory element, which includes a nucleotide sequence that confers selective expression upon an operatively linked nucleic acid molecule in the valve margin or dehiscence zone of a seed plant. Also provided by the invention are kits for producing a transgenic seed plant characterized by delayed seed dispersal, such kits containing a dehiscence zone-selective regulatory element.

A method and kit for synthesizing a nucleic acid molecule comprising at least one non-canonical nucleoside triphosphate using a double-mutant polymerase having a reduced discrimination between canonical and non-canonical substrates is disclosed. The method comprises incubating a template nucleic acid in a reaction mixture comprising the mutant nucleic acid polymerase and the appropriate canonical and non-canonical nucleoside triphosphates which are desired substrates for the mutant nucleic acid polymerase. The present invention is also a method of determining the sequence of a nucleic acid molecule using the mutant polymerase to create a nucleic acid molecule comprising at least one non-canonical nucleoside triphosphate.