Method for preparing thanatin based on escherichia coli prokaryotic expression system

Abstract

The invention relates to a method for preparing thanatin based on an escherichia coli prokaryotic expression system and belongs to the technical field of genetic engineering. A recombination gene comprises a fusion partner gene sequence, a methionine codon, a thanatin repetitive sequence and a stop codon, which are sequentially connected. The invention further provides a prokaryotic expression plasmid containing the recombination gene and escherichia coli containing the prokaryotic expression plasmid. The method for preparing the thanatin based on the escherichia coli prokaryotic expression system is characterized by comprising the following steps of (1) inducing escherichia coli to express recombination protein; (2) separating and purifying the recombination protein; (3) treating by cyanogen bromide to cut the recombination protein into a plurality of independent and complete thanatin; and (4) separating and purifying the thanatin. The innovation of the invention is as follows: the plurality of independent and complete thanatin is obtained in one step through splitting of the cyanogen bromide; and the expression quantity of the thanatin is high.

Description

technical field [0001] The invention relates to the preparation of deadin by using a prokaryotic expression system of Escherichia coli, and belongs to the technical field of genetic engineering. Background technique [0002] Thanatin, also known as death peptide, was discovered in the insect Podisus maculiventris. So far, among all known insect antimicrobial peptides, it has the broadest antibacterial spectrum and the strongest antibacterial activity. Composed of 21 amino acid residues, it has a simple structure and has antitumor activity. It has inhibitory effects on Gram-positive bacteria, Gram-negative bacteria and some fungi, and does not show hemolysis to mammalian cells. [0003] However, the content of natural antimicrobial peptides in insects is very small, and the separation and purification are difficult and the yield is low. However, the current research shows that direct expression of antimicrobial peptide genes in microorganisms by means of molecular biology an...

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Problems solved by technology

[0003] However, the content of natural antimicrobial peptides in insects is very small, so it is difficult to separate and purify, and the yield is low

However, the current research shows that using molecular biology and genetic engineering methods to directly express antimicrobial peptide genes in microorganisms may cause the host microorganisms to commit suicide and the expression products cannot be obtained, and are easily degraded by proteases.

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