Production in Escherichia of moricin, a novel type antibacterial peptide from the silkworm, Bombyx mori.

Moricin is a novel type antibacterial peptide recently isolated from the silkworm, Bombyx mori. Two foreign gene expression systems in Escherichia coli were employed to obtain a large amount of the peptide for further characterization. An artificial moricin gene was chemically synthesized and inserted into two expression vectors, pXa1 and pMAL-c2. The recombinant moricin was efficiently produced in E. coli as fusion proteins and released by chemical cleavage with cyanogen bromide or o-iodosobenzoic acid. Eleven milligrams of pure recombinant moricin was obtained from 2 L of E. coli culture. The primary structure and molecular mass of the purified recombinant moricin was the same as those of the natural moricin. In addition, the antibacterial activity of the recombinant moricin against E. coli and Staphylococcus aureus was comparable to that of the natural moricin.