Isolation and structure determination of a new antibacterial peptide pentaminomycin C from Streptomyces cacaoi subsp. cacaoi.

A new antibacterial peptide named pentaminomycin C was isolated from an extract of Streptomyces cacaoi subsp. cacaoi NBRC 12748T, along with a known peptide BE-18257A. Pentaminomycin C was determined to be a cyclic pentapeptide containing an unusual amino acid, Nδ-hydroxyarginine (5-OHArg), by a combination of ESI-MS and NMR analyses. The structure of pentaminomycin C was determined to be cyclo(-L-Leu-D-Val-L-Trp-L-5-OHArg-D-Phe-). Pentaminomycin C exhibited antibacterial activities against Gram-positive bacteria including Micrococcus luteus, Bacillus subtilis, and Staphylococcus aureus. The biosynthetic gene cluster for pentaminomycin C and BE-18257A was identified from the genome sequence data of S. cacaoi subsp. cacaoi.