Discovery of novel antimicrobial peptides, Brevilaterin V, from Brevibacillus laterosporus S62-9 after regulated by exogenously-added L-valine

Abstract

Properties of short-chain antimicrobial peptides (AMPs) depend on their primary structures. Brevibacillus laterosporus was previously found to secrete five AMPs. Herein, we discovered exogenously-added l-valine could regulate this strain to produce novel AMPs (named as Brevilaterin V) with new primary structures. Five novel Brevilaterins V with linear peptides were purified and characterized. They had high antimicrobial activities against 10 tested pathogenic bacteria. Brevilaterins V exhibited a good stability even treatment at 100 °C, or pH 2 or pH 12, for 2 h. Interestingly, all novel Brevilaterins V showed low hemolytic activities. In particular, the hemolytic rates of Brevilaterin V1 and Brevilaterin V2 were <5%; however, single changes in primary structure or a single extra methylene in the N-terminal fatty acid chain increase the hemolytic activity. The strategy of using amino acids in culture medium to regulate AMPs production by Br. laterosporus provides a basis for improvement of the range and properties of known AMPs.