92 results about "Molecular modification" patented technology

This invention provides an in vitro cell-free protein synthesis system, its reagent kit, and its applications, belonging to the field of protein synthesis technology. This invention improves an in vitro cell-free protein synthesis system based on Kluyveromyces lactis by adding exogenous L-arabinose, significantly enhancing the system's protein synthesis capacity. Furthermore, it provides a more efficient and higher-throughput in vitro protein synthesis reagent kit and a method for synthesizing exogenous proteins. The improvements provided by this invention can be achieved without molecular modification, are simple and convenient to operate, and save costs.

The invention discloses a 3-sterone-delta1-dehydrogenase mutant and application of the 3-sterone-delta1-dehydrogenase mutant in preparation of a steroid drug intermediate. The mutant is obtained by performing single mutation or multiple mutation on 551, 468, 48 and 157 sites of an amino acid sequence of 3-sterone-delta1-dehydrogenase as shown in SEQ ID NO: 1. The 3-ketosterone-delta1-dehydrogenase is subjected to molecular modification through directed evolution and semi-rational design, the mutant with improved enzyme activity is screened in a high-throughput mode, the mutant can effectively improve the conversion rate of a substrate 11alpha, 17alpha-dihydroxyprogesterone, and the substrate conversion rate of the mutant ISM-2 is improved to 92.4% compared with 36.7% before mutation.

The invention relates to the technical field of pharmaceutical preparations, in particular to a multiple nano emulsion adjuvant and a preparation method thereof. The multiple nano emulsion adjuvant is prepared from 2.73 to 6.37 g of an oil phase matrix based on 100 g of a raw material system, 0.10 to 0.25 g of a sterol compound; 0.212 to 0.424 g of a nonionic surfactant; 0.00050 to 0.00200 g of a triterpenoid saponin type active adjuvant; 0.010 to 0.020 g of an anionic polymer modifier; 0.005 to 0.015 g of a cationic polymer modifier; 70-90 g of a buffer solution; the total mass of the raw materials is 100 g. The nano emulsion adjuvant prepared by the invention can be stored for 6 months at 2-8 DEG C under a low sterol condition, the particle size change does not exceed + 5%, no crystallization or layering is generated, and the stability of the active adjuvant is remarkably improved.

The invention provides a high-activity chitinase mutant and application thereof in degradation of crustacean waste, and belongs to the technical field of enzyme engineering and agricultural waste conversion. According to the invention, chitinase PbChi from Paenibacillus barengltzii is subjected to molecular modification, and a plurality of chitinase mutants with high activity are successfully constructed by increasing the flexibility of a connexin, changing steric hindrance at a substrate catalytic crack inlet and changing catalytic residues in a beta sheet layer in a catalytic structural domain through calculation design and experimental verification; the chitinase mutant can effectively degrade shrimp shell meal, so that carapace waste is effectively utilized, and the chitinase mutant has a wide application prospect in the biological feed industry.

The invention provides an Akkermann Amuc1100 protein mutant as well as a preparation method and application thereof, wild Akkermann Amuc1100 protein is subjected to mutation modification through a molecular biological technical means, and the bioactivity of the Amuc1100 protein mutant subjected to molecular modification is obviously improved compared with that of the wild protein; compared with a wild type Amuc1100 protein, the wild type Amuc1100 protein has a better effect when being applied to the aspects of regulating intestinal immunity, relieving acute pancreatitis, promoting browning of white adipose cells, inhibiting obesity, relieving ulcerative colitis and the like, and a very good application prospect is provided for developing bioactive medicines with higher efficiency.

The invention discloses a preparation method of a nuclear magnetic resonance imaging contrast agent based on surface hepatocyte targeting molecule modification ferroferric oxide nanoparticles, which comprises the following steps: synthesizing ferroferric oxide nanoparticles (Fe3O4 NPs) by a thermal decomposition method, and connecting the Fe3O4 NPs with a ligand dopamine-PEG2000-EOB carrying hepatocyte targeting molecules by a ligand exchange method to obtain the nuclear magnetic resonance imaging contrast agent. The nanoparticles Fe3O4-EOB-PEG capable of carrying out selective T2 nuclear magnetic resonance imaging on the hepatocytes are formed. The method is simple and easy to operate, the controllability of the preparation process is high, the biocompatibility of the obtained product is good, T2 signals of hepatocytes can be remarkably improved, the good early diagnosis effect on liver tumors is achieved, and wide application prospects are achieved.

The invention provides a molecular modification design method for improving esterification activity of lipase. The method comprises the following steps: calculating a channel structure of lipase to be modified through CAVER ANALYST 2.0, determining a modification site through comprehensive measurement of other calculation tools, establishing a mutant library by adopting NNK degenerate codons for site-saturated mutation, and screening out excellent mutants with improved esterification performance by adopting a microwell plate screening method based on a copper soap complexing method. According to the candida antarctica lipase B mutant M5 disclosed by the invention, in various different types of esterification reactions, the catalytic efficiency of the mutant M5 is improved by 4.5 times or more than that of a wild type. The molecular modification design method disclosed by the invention can be used for improving the esterification performance of the lipase and has relatively wide esterification reaction application applicability, so that the lipase mutant can play an important role in industrial application in the fields of foods, medicines or biodiesel and the like.

The application discloses a carbonyl reductase mutant and application thereof in preparation of (R)-8-chloro-6-hydroxyoctanoate compounds. The application relates to a mutant of carbonyl reductase with improved catalytic performance and stereoselectivity after rational molecular modification, a recombinant expression plasmid containing the mutant gene of the enzyme, a recombinant expression transformant, a preparation method of the recombinant enzyme, and application of the recombinant enzyme or the recombinant cell as a catalyst in asymmetric reduction of 8-chloro-6-carbonyloctanoate compounds (I) to prepare (R)-8-chloro-6-hydroxyoctanoate compounds (II), in particular, in an intermediate (R)-8-chloro-6-hydroxyoctanoate methyl ester of thioctic acid. The disclosed carbonyl reductase SsCR mutant has the advantages of high reaction efficiency and high catalytic activity, and exhibits the advantages of high substrate concentration, low catalyst consumption and short reaction time in the process of catalytic preparation of the compound (II).

The application belongs to the technical field of cosmetic and pharmaceutical chemistry, and discloses a 2,4-dihydroxyphenyl thiazole derivative and application thereof. The 2,4-dihydroxyphenyl thiazole derivative has the structure shown in the following formula: wherein n1 and n2 are each independently 1, 2, 3 or 4; and R is methyl or ethyl. Compared with existing peptide amido compounds, the 2,4-dihydroxyphenyl thiazole derivative of the application, while maintaining the active structure of the parent nucleus, significantly improves the solubility and physicochemical stability through molecular modification, and optimizes the pharmacokinetic characteristics. The derivative can effectively inhibit the activity of tyrosinase, and can be used as an active ingredient to prepare a novel tyrosinase inhibitor, related whitening and freckle-removing cosmetics and a drug for tyrosinase-related diseases.

The application discloses a kind of polypeptide modified long afterglow nano-complex and its preparation method and application, nano-complex, for core-shell structure, core-shell structure is composed of the core body in inside and the shell that surrounds core body, core body is long afterglow nanomaterial, shell is by polypeptide modification and modified molecule modification, and drug loaded dendritic polymer;The nano-complex of the application can realize multiscale imaging to osteoclast, through in vivo afterglow imaging and in vivo two-photon microscopic imaging, the morphology, migration and distribution of osteoclast can be more accurately analyzed, avoid photo toxicity and background interference, improve imaging sensitivity;The nano-complex of the application is loaded with osteoporosis treatment drug alendronate ALN, and treatment drug can be replaced according to actual demand, and treatment scheme is adjusted, so that the drug loading system has universality.

The invention discloses a surface-enhanced Raman probe as well as a preparation method and application thereof, and belongs to the technical field of biomedical imaging and stem cell therapy. The preparation method comprises the following steps: coating an ultrathin silver shell layer on the surface of gold nanoparticles to obtain Au-coated Ag particles; 4-sulfydryl phenylboronic acid pinacol ester molecules are modified on the surface of Au (at) Ag to form a Raman report layer, then sulfydryl-polyethylene glycol is introduced to realize biological orthogonal coupling, and the modified SERS probe is obtained through bovine serum albumin modification; jointly incubating the modified SERS probe and the azidation-labeled mouse bone marrow mesenchymal stem cells, so as to form an mmol / LSC-SERS composite probe; the obtained probe has good biocompatibility, stability and anti-interference capability and is suitable for a complex physiological environment, and the preparation method is simple and good in repeatability, is completely carried out in a water phase and does not need an organic solvent.

A method for producing a food product with gluten molecule modification, comprising the steps of: a) mixing at least gluten-containing flour with at least one liquid until a homogeneous mixture is obtained; b) containing the mixture in a gas-tight container and extracting air from the gas-tight container within 15 minutes after obtaining the mixture according to step a) in order to obtain a vacuum of at least equal to 70% inside the gas-tight container and maintaining the homogeneous mixture inside the container at a vacuum for a period of at least equal to 3 hours, thereby obtaining a mixture; c) obtaining a food product using the mixture obtained at the end of step b).

The application belongs to the field of bioengineering. The application provides a molecular modification design method for improving the hydrophobicity of the catalytic center of bacillus subtilis protease, which comprises the following steps: searching for a resolved bacillus subtilis protease crystal structure in a protein database PDB, generating an enzyme-substrate complex by docking a hexapeptide substrate through a Glide mode of software, calculating the polar charge of each amino acid residue of polar atoms N and O and H combined thereof within a 10 angstrom range of the catalytic center amino acid of the bacillus subtilis protease by using a PPC force field, calculating the absolute value sum of the polar charge, selecting a potential mutation site of the bacillus subtilis protease, virtually mutating the potential mutation site into a large steric hindrance nonpolar amino acid, calculating the absolute value sum of the polar charge of polar atoms N, O and H within a 10 angstrom range of the catalytic center amino acid of the single-point mutant by using the PPC force field, selecting a virtual bacillus subtilis protease single-point mutant, expressing the mutant and iteratively mutating, re-expressing, obtaining a modified bacillus subtilis protease mutant, and verifying the hydrophobicity. The molecular modification design method can quickly and effectively reduce water molecules in the catalytic center of the bacillus subtilis protease and improve the hydrophobicity thereof. It has been verified that the enzyme modification method is effective and reliable.

A method for producing an Fc-containing molecule modifying reagent, including reacting a protein or peptide with a crosslinking agent in the presence of a base having a stronger basicity than pyridine to bond an amino group in the protein or peptide with the crosslinking agent.

According to the invention, beta-glycosidase which has a catalytic effect on vincoside, loganin and strictosamide is selected, and a foundation is laid for diversity and possibility of an aglycone production process. By researching the three-dimensional structure information of the Gelsemium elegans Beta-glycosidase, a zymoprotein structure information basis is provided for molecular modification of the Gelsemium elegans Beta-glycosidase, enzyme variants capable of improving substrate selectivity, thermal stability and catalytic efficiency are obtained more efficiently, and the requirements of industrial application are met; the invention provides a truncated mutant enzyme with improved enzymatic activity, and through induced expression and activity screening, it is found that the enzyme activity of the obtained mutant enzyme to loganin and strictosamide is about two times higher than that of a wild enzyme.

A diaminopimelate dehydrogenase mutant and a use in D-amino acid synthesis. A diaminopimelate dehydrogenase mutant obtained by performing molecular modification on a Bacillus thermozeamaize diaminopimelate dehydrogenase, a nucleic acid encoding the diaminopimelate dehydrogenase mutant, a recombinant expression vector containing the nucleic acid, a recombinant expression transformant containing the recombinant expression vector, and a use of the diaminopimelate dehydrogenase mutant in the synthesis of a D-amino acid by means of the asymmetric reductive amination of a 2-keto acid. Compared with other D-biphenylalanine synthesis methods, the present invention has a simple route, a high theoretical yield, good atom economy, and a product optical purity of more than 99%. Therefore, the present invention relates to an environmentally-friendly, highly-stereoselective and green biological synthesis method, and has good prospects for application in actual production of D-biphenylalanine and other D-amino acids.

The present application relates to diaminopimelic acid dehydrogenase mutant and its application in D-phenylglycine synthesis. The present application discloses a diaminopimelic acid dehydrogenase mutant which is obtained by molecular modification of diaminopimelic acid dehydrogenase from Bacillus thermozeamaize, a nucleic acid coding the diaminopimelic acid dehydrogenase mutant, a recombinant expression vector containing the nucleic acid, a recombinant expression transformant containing the recombinant expression vector, and the use of the diaminopimelic acid dehydrogenase mutant in the synthesis of D-phenylglycine from asymmetric reduction of aminated benzoylformic acid. Compared with other D-phenylglycine synthesis methods, the route of the present application is simple, the theoretical yield is high, the atom economy is good, the substrate concentration and the product yield are high, and the optical purity of the product is greater than 99%. Therefore, the present application belongs to an environmentally friendly, high stereoselectivity and green and environmentally friendly biosynthesis method, and has good application prospect in the actual production of D-phenylglycine.

The application discloses a preparation method of chitosan microspheres for cell immobilization and drug delivery, and relates to the field of chitosan microsphere preparation. The application carries out deacetylation on chitin through a microwave induction process technology combined with enzymes, carries out heavy metal green chelation on chitosan by using glutamic acid diacetic acid tetrasodium or citric acid, further improves the extraction and removal capacity of the chelating agent on residual metal ions by using a carbonate salt solubilization technology, and separates and hydrolyzes trace amounts of protein and lipids in the crude chitosan by selecting appropriate biological enzymes to obtain refined chitosan. Meanwhile, the refined chitosan is subjected to enzymatic molecular modification by applying transglycosylation or oxidase, and finally, the chitosan microspheres are prepared by using a green and environment-friendly spray drying method. The chitosan microspheres prepared by the application are smooth in shape, uniform in size, have a particle size of 1-250 mu m, and have a shell-core structure. The chitosan immobilized enzyme widens the application of chitosan in the fields of medicine, food and the like.

The invention belongs to the technical field of genetic engineering and synthetic biology, and particularly relates to a recombinant saccharomyces cerevisiae strain for producing chrysoeriol as well as a construction method and application of the recombinant saccharomyces cerevisiae strain. On the basis of the advantages of eukaryotic metabolism and genetic manipulation of saccharomyces cerevisiae, a saccharomyces cerevisiae strain W303 is used as a chassis cell, galactose dependence regulation of a bidirectional promoter GAL1-GAL10 is relieved by knocking out a GAL80 gene, a pyruvate decarboxylase gene PDC5 is knocked out, accumulation of by-products such as ethanol is limited, carbon metabolism flux is redirected to a phenylpropanoid metabolism pathway, and the yield of the phenylpropanoid is increased. According to the present invention, the key enzyme OMT-derived O-methyltransferase OMT related molecular modification is screened, the de novo synthesis of chrysoeriol is achieved for the first time, the method has advantages of clear genetic background, sustainable modification and the like, and the established synthesis module and the established regulation and control method provide the referential technical framework for the microbial synthesis of other flavonoid compounds.

This invention discloses an internal standard-assisted petal-shaped SERS nanoprobe, its preparation method, and its applications. The internal standard-assisted petal-shaped SERS nanoprobe of this invention is a core-molecule-shell structure gold nanoprobe consisting of a gold nanosphere core, an internal standard modifying molecule, a petal-shaped gold nanoshell, and a recognition molecule, 4-nitrobenzenethiophenol. The internal standard modifying molecule is a Raman signal molecule with nitrile, alkyne, or azide functional groups. This invention uses a Raman signal molecule as an internal standard modifying molecule to modify the gold nanosphere core. The corrected working curve exhibits good reproducibility and small error, improving the reliability of the detection results. Growing a petal-shaped gold nanoshell on the molecular layer of the internal standard modifying molecule enhances the SERS activity both inside and outside the SERS substrate, and the petal-shaped shell increases the surface area of ​​the SERS substrate. Furthermore, the recognition molecule of this invention enables ratiometric Raman detection of hydrogen sulfide, effectively reducing background signal interference and improving detection sensitivity.

The application discloses a method for catalytically producing 5-fluorouracil and application, and belongs to the technical field of biology. The method uses 5-fluoroorotic acid as a substrate and orotidine-5'-phosphate decarboxylase as a catalyst to efficiently catalyze the synthesis of 5-fluorouracil. The catalytic efficiency is further improved by molecular modification of orotidine-5'-phosphate decarboxylase, the efficient and green production of 5-fluorouracil is realized, and the application of 5-fluorouracil in the fields of medicine and the like is promoted.

The invention relates to the technical field of medical detection, in particular to a nanoprobe for simultaneously detecting and inhibiting VCAM-1mRNA expression as well as a preparation method and application of the nanoprobe. The nano particle takes a nano Au particle as a core, and p-mercaptocyanophenyl (4-MBN) serving as a Raman signal internal standard molecule is modified on the surface of the Au core; the nano particle takes a gold layer as a shell, and a VCAM-1mRNA targeting recognition sequence segment is fixed on the Au shell; and the tail end of the VCAM-1 mRNA targeted recognition sequence segment is modified with a Raman reporter molecule Cy5. The recognition sequence segment on the nanoprobe can be specifically combined with VCAM-1mRNA to form a rigid double strand, so that Cy5 is far away from the surface of the gold core-shell nanoparticle, the SERS signal strength of Cy5 is weakened, the position of 4-MBN located on a spacing layer is unchanged, and the SERS signal of the 4-MBN is also unchanged. The expression of the VCAM-1 protein can be inhibited by the accompanying mRNA consumption in the detection process, so that the synchronous monitoring and treatment intervention of the atherosclerosis disease closely associated with the expression of the VCAM-1 are realized.

The application provides a kind of tea polyphenol ester-RNA self-assembly and hybrid nanovesicle of probiotic outer membrane vesicle and preparation method thereof, which first adjusts the hydrophilicity and hydrophobicity of tea polyphenol EGC through molecular modification strategy, and the EGC palmitate obtained by modification can directly wrap RNA and self-assemble into tea polyphenol ester-RNA nanovesicle, which has superior encapsulation capacity. Further introduce OMVs as intestinal targeted delivery carrier and fuse with RNA-tea polyphenol nanovesicle to form a structure stable hybrid vesicle. The hybrid vesicle of the application ingeniously integrates the advantages of both sides: tea polyphenol ester-RNA nanovesicle ensures efficient encapsulation of RNA, and OMVs provide natural protection for its translocation through gastrointestinal tract, and promote intestinal cell uptake with its inherent bioadhesion. This strategy can effectively promote the encapsulation and stabilization of oral RNA delivery.

The invention relates to SERS (Surface Enhanced Raman Scattering) sensing test paper for detecting trace target molecules in tears as well as a preparation method and a detection method and belongs to the field of biosensing and spectral analysis. At least one of the problems of insufficient detection sensitivity, poor anti-pollution capability, low selectivity, incapability of rapid and on-site instant detection and the like in the existing tear biomarker detection technology is solved. The SERS sensing test paper comprises a porous fiber matrix and an SERS active nano composite material loaded on the porous fiber matrix, the SERS active nano composite material is precious metal nano particles (at) HZIF modified by Raman reporter molecules, and the SERS active nano composite material is of a core-shell structure. According to the invention, ultrasensitive, anti-pollution and rapid on-site detection of trace target molecules (such as histamine) in tears is realized.

The present application provides an anti-ultraviolet polydimethylsiloxane food packaging coating and a preparation method thereof, which realizes the dual synergy of anti-ultraviolet and food preservation function through molecular modification, and introduces degradable materials to enhance environmental protection. The coating embeds anti-ultraviolet groups and preservation groups into the polydimethylsiloxane main chain through chemical bonds, avoiding the migration of traditional additives. A one-step in-situ polymerization process is used to ensure uniform distribution of functional groups, solving the problems of uneven function and migration. The coating provides ultraviolet protection, antibacterial, ethylene absorption, water retention, and prolongs the shelf life of food. The coating also uses degradable materials to reduce environmental pollution. It is suitable for outdoor circulation and transparent packaging scenarios, providing an efficient, safe and environmentally friendly packaging solution.

The invention belongs to the technical field of biochemistry, and particularly discloses a novel LNP gene drug siRNA delivery carrier and a construction method thereof. The construction method comprises the following steps: by taking a DNA nanocube as a basic carrier, loading siRNA on the surface of the DNA cube in a base complementary pairing manner, then coating liposome on the outer layer of the cube by utilizing a DNA structure-assisted phospholipid membrane self-assembly technology, and modifying polypeptide target molecules on the outer surface of the liposome by adopting a post-insertion method, so as to obtain the siRNA-modified liposome. The siRNA nano delivery carrier capable of delivering siRNA to tumor tissues in a targeted manner is obtained. The delivery carrier constructed by the invention can realize targeted efficient delivery of siRNA, and effectively solves the following problems existing in current siRNA delivery: 1) the siRNA is easy to degrade in the delivery process, lysosome escape is difficult, and the delivery efficiency is low; 2) problems of potential cytotoxicity, easy induction of immune response and difficult metabolism of a delivery carrier, and 3) problems of liposome instability, low drug loading capacity and difficult size control.

The invention provides a modification method of an antibody, the modification method adopts a modification molecule with a cage-shaped structure to modify the antibody, and after modification, the rigid structure of the antibody molecule is enhanced, the stability is improved, and the half-life period is prolonged. Meanwhile, by adjusting the addition amount of the modified molecules, the obtained antibody can present a nanoparticle aggregation structure, and the activity of the antibody is further improved.

This invention discloses a bifunctional small-molecule PEG-modified recombinant humanized collagen and its preparation method. The method includes the following steps: preparing a borate buffer solution containing sodium cyanoborohydride, pH 7.5-8.5; dissolving lyophilized recombinant collagen powder in the buffer solution to obtain a substrate solution; adding crosslinking agent powder to the substrate solution according to a molar ratio of free lysine to crosslinking agent of 1:(1.5-4.0); the crosslinking agent is a bifunctional small-molecule PEG with PEG as the backbone and groups at both ends that can couple with the amino groups of collagen; reacting at 4°C in the dark for 2-5 hours. This invention not only overcomes the bottleneck of anti-enzymatic stability but also transforms recombinant humanized collagen into a multi-arm macromolecular crosslinking substrate with highly active groups on its surface, providing key chemical bonding sites for its subsequent targeted coupling or anchoring to polymer networks such as hydrogels.