Isolation of a new antibacterial peptide achromosin from Streptomyces achromogenes subsp. achromogenes based on genome mining

Abstract

Here, we describe isolation and structure determination of a new antibacterial peptide named achromosin from Streptomyces achromogenes subsp. achromogenes based on genome mining. The biosynthetic gene cluster of achromosin includes a precursor peptide gene acrA and modification enzyme genes acrC, acrB1, and acrB2. Achromosin is a class II lasso peptide with the amino acid sequence GIGSQTWDTIWLWD, featuring a macrolactam ring between the amino residue of Gly1 and the β-carboxyl residue of Asp8 without disulfide bonds. It exhibits antibacterial activity against Micrococcus luteus (10 μg per disk showing an inhibitory zone of 11 mm diameter) but no activity against other tested microorganisms. The biosynthetic genes of achromosin show similarity to those of chaxapeptin, and no transport protein-coding gene is found near the cluster.