5 results about "Selective cleavage" patented technology

Some embodiments of the methods and compositions provided herein relate to the selective cleavage of a target nucleic acid. Some such embodiments include the selective cleavage of a target nucleic acid that is associated with a DNA-binding protein or comprises a methylated CpG island, with a recombinant nuclease. In some embodiments, the DNA-binding protein comprises a chromatin protein. Some embodiments also include the enrichment of non-target nucleic acids in a sample by selective cleavage of target nucleic acids in the sample, and removal of the cleaved target nucleic acids from the sample.

The present application belongs to the technical field of lignin depolymerization, and particularly relates to a method for selectively breaking lignin beta-O-4 connection mediated by small molecule mercaptan. In an H-type electrolytic cell, the anode electrolytic cell uses a buffer as an electrolyte, the cathode electrolytic cell uses a lignin beta-O-4 model compound as a reaction substrate, and an acetonitrile / buffer mixed solution of small molecule mercaptan is used as an electrolyte to perform an electrochemical cleavage reaction. Among them, the small molecule mercaptan medium acts as a single electron transfer medium, and under the catalysis of electric current, the key C β -O bond in the lignin beta-O-4 model compound can be efficiently and selectively broken at room temperature and normal pressure to obtain corresponding phenolic and ketone monomers, solving the problems of high temperature and high pressure, expensive catalysts and the like in the lignin reduction pathway depolymerization.

The invention discloses a thermosetting polyurethane foam recycling method based on ethyl acetoacetate selective cracking biuret crosslinking points, and belongs to the technical field of polyurethane foam recycling. The preparation method comprises the following steps: mixing polyurethane foam with ethyl acetoacetate for reaction to obtain degradation liquid; mixing the obtained degradation liquid with methacrylic acid 2-isocyanate ethyl ester, and adding a photoinitiator to obtain a photocuring precursor; and finally, carrying out 3D printing on the photocuring precursor, and drying to obtain a regenerated product. Crosslinked biuret bonds of waste polyurethane are selectively broken through ethyl acetoacetate, meanwhile, non-crosslinked urethane bonds and urea bonds are reserved, the bond breaking amount is small, depolymerization and re-bonding reagent consumption is low, depolymerization product components are uniform, complex and expensive separation and purification are not needed, no by-product is generated in the reaction, 100% resource reutilization can be achieved, and the method is suitable for industrial production. Meanwhile, the depolymerized product can be prepared into a high-added-value product or used as a pressure-sensitive adhesive.

This specification discloses a method for high-throughput evaluation of the in vitro cleavage activity of a CRISPR / Cas system. The inventors of this application have implemented this method based on the concept that an in vitro environment can be simulated by immobilizing cells to inhibit their viability, while partially utilizing existing established high-throughput evaluation methods for in vivo environmental activity. Furthermore, this specification discloses a model for predicting the cleavage activity of a CRISPR / Cas system and its application method. This includes: 1) collecting cleavage activity data using various combinations of target-guide vectors; 2) obtaining two or more alignment patterns to augment the data when the target nucleic acid and guide nucleic acid do not match; and 3) inventing the model by developing a method for training the model using aligned target nucleic acid sequences and aligned guide nucleic acid sequences as key input variables, and applying the model in various ways. Additionally, this specification discloses a method for enriching rare nucleic acids using a CRISPR / Cas system when a sample contains trace amounts of rare nucleic acids and a large amount of background nucleic acids. The inventors selected a guide nucleic acid (optimized guide nucleic acid) that promotes selective cleavage of the nucleic acid to be cleaved (rare nucleic acid or background nucleic acid) relative to nucleic acids with similar sequences (background nucleic acids or rare nucleic acids), and used it to develop a rare nucleic acid enrichment method.

This invention relates to the optimization and application of C1 type botulinum toxin light chain (BoNT / C1LC) mutants. Using the selectively Syntaxin-1 cleaving mutant BoNT / C1α-51 as a template, this invention employs PCR site-directed mutagenesis to replace amino acids at positions 53-51 and evaluates enzyme activity at the cellular level. The results show that mutants 53Y, 52H53Y, 51D52H53Y, 51S52H53Y, 51G52H53Y, 51A52H53Y, and 51Y52H53Y exhibit no cleavage activity against the substrate SNAP-25, but retain cleavage activity against Syntaxin-1. Among these, 52H53Y, 51S52H53Y, and 51G52H53Y show superior Syntaxin-1 cleavage activity compared to BoNT / C1α-51. The mutants provided by this invention, which replace full-length BoNT / C1LC or are fused with a membrane-penetrating peptide and are active only for Syntaxin-1, can be used in the preparation of medical aesthetic products and related drugs that supplement clinical responses to or non-responses to botulinum toxin type A, and whether or not resistance has been developed. Mutants with Syntaxin-1 cleavage activity superior to BoNT / C1α-51 can be used in the preparation of drugs for Syntaxin-1-mediated hypersecretion diseases. Mutants such as 51F52H53Y have no cleavage activity against both SNAP-25 and Syntaxin-1 and can be used in the preparation of targeted delivery drugs for the nervous system using full-length botulinum toxin as a carrier.