Promoinducin, a Novel Thiopeptide Produced by Streptomyces sp. SF2741

Abstract

Our continued screening to find tipA promoter-inducing substances resulted in the isolation of promoinducin from a mycelial extract of Streptomyces sp. SF2741. Based on various 1D- and 2D-NMR studies, including field gradient (FG)-COSY, HSQC, FG-HMBC, phase-sensitive ¹³C-decoupled HMBC and NOESY experiments, promoinducin's structure was established to be a thiopeptide composed of threonine, some unusual amino acids masked at their carboxyl groups by thiazole or methyloxazole rings, sulfomycinamate and five dehydroalanine residues. Promoinducin induced the tipA promoter at 40ng/ml, and also exhibited strong antibacterial activity against some Gram-positive bacteria.