8 results about "Double mutation" patented technology

The invention relates to the technical field of biology, in particular to a cis-trans typing method for drug-resistant gene mutation EGFR T790M / C797S. The invention provides an EGFR (Epidermal Growth Factor Receptor) T790M / C797S cis-trans typing method based on a locked nucleic acid LNA (Low Nucleic Acid) probe, ultrahigh-specificity DNA (Deoxyribose Nucleic Acid) polymerase and a primer probe combination. The typing method can be used for accurately distinguishing EGFR T790M / C797S double-mutation cis-configuration and trans-configuration; meanwhile, the kit has the advantages of high sensitivity, high specificity, simple steps and low cost, is suitable for detecting low-abundance samples such as circulating tumor DNA (ctDNA) and can meet the clinical rapid detection requirement.

The invention relates to the field of enzyme engineering, and provides a BhrPETase variant capable of improving stability through site-specific replacement under the background of Bhr6M (SEQ ID NO: 1) and application of the BhrPETase variant, and the replacement is M57I and / or S184H, preferably double mutation M57I / S184H. The variant shows remarkable thermal stability and storage stability under a unified measurement caliber: the condition t1 / 2 at 90 DEG C is greater than or equal to 400 minutes, the condition t1 / 2 at 70 DEG C is greater than or equal to 7 days, and the residual activity after 30 days of storage at 30 DEG C is greater than or equal to 90%. The invention also discloses a nucleic acid encoding the variant, a vector, a recombinant host, an enzyme preparation, and a method for depolymerizing PET and a copolymer thereof in a process temperature range of 70-90 DEG C. Compared with a control Bhr6M, the variant maintains more lasting activity in high-temperature and long-period operation, is suitable for PET substrates with different forms and crystallinity, reduces the enzyme supplementing frequency and improves the stability of a device.

To provide a human interferon-beta mutant having a double mutation and a method for improving the safety of the human interferon-beta mutant.SOLUTION: Provided are a human interferon-beta variant comprising an amino acid sequence in which the 17th amino acid cysteine of human interferon-beta is substituted with serine and the 27th amino acid arginine is substituted with threonine, and a method for improving the stability of a human interferon-beta R27T variant, the method comprising the step of changing the 17th amino acid cysteine of a human interferon-beta R27T variant, in which the 27th amino acid arginine of human interferon-beta is substituted with threonine, to serine.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of green chemistry, and particularly relates to a method for modifying a flexible ring region of nitrile hydratase and application of the method. The specific method comprises the following steps: carrying out double mutation on nitrile hydratase sites alpha D38 and alpha I152, or carrying out double mutation on nitrile hydratase sites alpha E157 and beta G197, or carrying out quadruple mutation on the nitrile hydratase sites alpha D38, alpha I152, alpha E157 and beta G197, so as to construct the nitrile hydratase mutant with improved thermal stability. The thermal stability of the nitrile hydratase modified by mutation is greatly improved. The mutant nitrile hydratase can keep the conformation and activity for a longer time, the resistance to external thermal interference is enhanced, and the half-life period for catalyzing an adiponitrile reaction is remarkably prolonged, which is the inherent excellent attribute of the mutant nitrile hydratase as a catalyst, and the mutant nitrile hydratase has important reference significance for research on improvement of the thermal stability of the nitrile hydratase.

Provided in the present invention are a mutant of Burkholderia cepacia lipase, and a recombinant expression vector thereof and the use thereof. The mutant comprises P131S, T132A, T251A, T251S, P131A, P131Q, T132G, Q88S or P113A single mutation, Q88S and P113A double mutation, and combinations of multi-site mutations including combination 1 of Q88S, P113A, T132G and L287S, combination 2 of Q88S, P113A, P131S and L287S, and combination 3 of Q88S, P113A, P131S and T251A.

The invention belongs to the technical field of green chemistry, and particularly relates to a method for modifying a flexible ring region of nitrile hydratase and application of the method. The specific method comprises the following steps: carrying out double mutation on nitrile hydratase sites alpha D38 and alpha I152, or carrying out double mutation on nitrile hydratase sites alpha E157 and beta G197, or carrying out quadruple mutation on the nitrile hydratase sites alpha D38, alpha I152, alpha E157 and beta G197, so as to construct the nitrile hydratase mutant with improved thermal stability. The thermal stability of the nitrile hydratase modified by mutation is greatly improved. The mutant nitrile hydratase can keep the conformation and activity for a longer time, the resistance to external thermal interference is enhanced, and the half-life period for catalyzing an adiponitrile reaction is remarkably prolonged, which is the inherent excellent attribute of the mutant nitrile hydratase as a catalyst, and the mutant nitrile hydratase has important reference significance for research on improvement of the thermal stability of the nitrile hydratase.

The application discloses an aldolase mutant and application thereof. The aldolase mutant is obtained by double mutation of F184Y and W199F on wild-type aldolase enzyme from Escherichia coli, and the amino acid sequence of the aldolase mutant is shown as SEQ ID No. 4. The specific activity of the aldolase mutant in catalyzing synthesis of (4R, 6S)-6-chloromethyl-2, 4-dihydroxy-2H-pyran is increased to nearly 4 times of that of the wild-type enzyme, and the substrate tolerance is also more superior.

This application relates to a drug lead compound with ALK G1202R / L1196M double mutation inhibitory activity, a virtual screening method, and its application. The method includes: obtaining resolved single-mutant complex structures from a database; constructing screening models based on the complex structures and performing standardized preprocessing on the crystal structures in each model; optimizing the structure and preparing the conformation of the compound library to be screened; determining the docking method, screening the optimal screening model, clustering the optimal screening model, docking it with the compound library to be screened, and obtaining drug lead compounds with ALK G1202R / L1196M double mutation inhibitory activity through drug-like property filtering, ligand structure clustering, and ADMET property prediction. The technical solution of this application can accurately screen ALK G1202R / L1196M double mutation inhibitory lead compounds, shortening the research and development cycle, reducing costs, and has clinical translational value.