A kind of Escherichia coli fusion expression plectasin, its preparation method and application

Abstract

The invention discloses a fusion expression plectasin, a preparation method and application thereof. The amino acid sequence of the recombinant plectasin is SEQ ID NO:1; and a nucleotide sequence designed according to an escherichia coli preferred codon is SEQ ID NO:2. According to the invention, a prokaryotic expression vector is utilized to construct the escherichia coli BL21 (DE3) host strain capable of expressing plectasin-thioredoxin fusion protein. The strain is subjected to multiplication culture, isopropyl-beta-D-isopropylthiogalactoside induction expression is carried out, centrifugation is performed to harvest thallus, the thallus is cracked, then centrifugation is conducted to acquire the supernatant, and affinity chromatography purification is carried out to obtain plectasin fused protein, the growth of gram positive staphylococcus aureus, streptococcus pneumoniae and the like can be significantly inhibited without removing thioredoxin by enzyme digestion. According to the invention, plectasin fused protein has obvious bacteriostatic effect without removing fusion protein by enzyme digestion, and the production cost is greatly reduced.

Description

Background technique [0001] Antimicrobial peptides are a kind of small peptide substances widely existing in natural organisms. It is an important part of the body's innate immune system. Because antimicrobial peptides have a wide range of inhibitory effects on bacteria, fungi, parasites, viruses, tumor cells, etc., and with the emergence of more and more antibiotic-resistant microorganisms, antimicrobial peptides have a good reputation in the pharmaceutical industry and food additives. Application prospects. Mycelium is a kind of fungal defensin, which is a kind of antibacterial peptide. The mature functional fragment of hyphamycin has 40 amino acids and its molecular weight is 4.4kD. Its biological activity is mainly manifested in its strong bactericidal effect on Gram-positive bacteria, especially Streptococcus pneumoniae and Streptococcus pyogenes. , Staphylococcus aureus, etc., have an antibacterial effect equivalent to penicillin and vancomycin. Studies have shown that ...

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Problems solved by technology

[0002] At present, there have been some researches on the expression of plectasiacin gene engineering at home and abroad, but because the pphaceasin antimicrobial peptide has antibacterial effect, the expression host such as Escherichia coli expresses the plectasiacin antimicrobial peptide will feedback inhibit the activity of host cells , affect the further expression of plectasin antibacterial peptides, so yeast expression is often used in the genetic engineering research of plectasin antimicrobial peptides, or expression in Escherichia coli plus a large fusion protein is performed together to remove the fusion protein tag and purify However, the cost of the two different expression methods is relatively high, and it is not suitable for widespread use in animal feed additives, antibacterial drug preparations, health products or preservatives, so there is no mature plectasin antimicrobial peptide product on the market

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