High-Yield Soluble Expression and Simple Purification of the Antimicrobial Peptide OG2 Using the Intein System in Escherichia coli

الملخص EN

OG2 is a modified antimicrobial peptide, that is, derived from the frog peptide Palustrin-OG1.

It has high antimicrobial activity and low cytotoxicity, and it is therefore promising as a therapeutic agent.

Both prokaryotic (Escherichia coli) and eukaryotic (Pichia pastoris) production host systems were used to produce OG2 in our previous study; however, it was difficult to achieve high expression yields and efficient purification.

In this study, we achieved high-yield OG2 expression using the intein fusion system.

The optimized OG2 gene was cloned into the pTWIN1 vector to generate pTWIN-OG2-intein2 (C-terminal fusion vector) and pTWIN-intein1-OG2 (N-terminal fusion vector).

Nearly 70% of the expressed OG2-intein2 was soluble after the IPTG concentration and induction temperature were decreased, whereas only 42% of the expressed of intein1-OG2 was soluble.

Up to 75 mg of OG2-intein2 was obtained from a 1 l culture, and 85% of the protein was cleaved by 100 mM DTT.

Intein1-OG2 was less amenable to cleavage due to the inhibition of cleavage by the N-terminal amino acid of OG2.

The purified OG2 exhibited strong antimicrobial activity against E.

coli K88.

The intein system is the best currently available system for the cost-effective production of OG2.