Decreasing DNA library concentration based aptamer screening method and aptamer

Abstract

The invention relates to a decreasing DNA library concentration based aptamer screening method and an aptamer. The method includes: a protein-magnetic bead crosslinking step, i.e. subjecting control protein and target protein to crosslinking with magnetic beads respectively; a first-round screening step, i.e. adding a target protein-magnetic bead composite into an initial DNA library solution to conduct first-round screening; a repeated screening step, i.e. diluting the screening product of the previous round by 2-10 times to serve as the DNA library solution of the next round screening so as to carry out the second to the N-th round screening; and a DNA synthesis step, i.e. conducting cloning and sequencing on the final screening product, and synthesizing a numerically superior DNA sequence with high affinity, thus obtaining the aptamer. The method provided by the invention takes low concentration as a screening condition to screen out high affinity aptamer that can bind with the target protein under an extremely low concentration, thus greatly reducing the influence of PCR conditions on the screening process, significantly shortening the screening time, reducing the screening round number, and improving the success rate of screening.

Description

technical field [0001] The invention belongs to the field of molecular biology, and more specifically relates to a nucleic acid aptamer screening method based on decreasing concentration of a DNA library and a nucleic acid aptamer. Background technique [0002] Aptamers refer to single-stranded oligonucleotide chain molecules (DNA or RNA) that can specifically bind to target molecules, generally less than 100mer. Compared with antibodies, the molecular recognition function between nucleic acid aptamers and target molecules is very similar to that of antibodies, but the range of target molecules is wider, including toxins with weak immunogenicity and non-immunogenic substances and those capable of recognizing monoclonal antibodies. Similar substances that cannot be distinguished have higher specificity and higher affinity than antibodies. Due to their unique advantages in structure and performance, nucleic acid aptamers are increasingly widely used in basic biomedical resear...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a nucleic acid aptamer based on the decreasing concentration of the DNA library, aiming at the defect that PCR amplification is used after each round of screening in the existing nucleic acid aptamer screening method, resulting in a complicated technical screening process and a low screening success rate. Aptamer screening method and nucleic acid aptamer

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