Characterization of a new ScbR-like gamma-butyrolactone binding regulator (SlbR) in Streptomyces coelicolor

Abstract

gamma-Butyrolactones in Streptomyces are well recognized as bacterial hormones, and they affect secondary metabolism of Streptomyces. gamma-Butyrolactone receptors are considered important regulatory proteins, and various gamma-butyrolactone synthases and receptors have been reported in Streptomyces. Here, we characterized a new regulator, SCO0608, that interacted with SCB1 (gamma-butyrolactone of Streptomyces coelicolor) and bound to the scbR/A and adpA promoters. The SCO0608 protein sequences are not similar to those of any known gamma-butyrolactone binding proteins in Streptomyces such as ScbR from S. coelicolor or ArpA from Streptomyces griseus. Interestingly, SCO0608 functions as a repressor of antibiotic biosynthesis and spore formation in R5 complex media. We showed the existence of another type of gamma-butyrolactone receptor in Streptomyces, and this SCO0608 was named ScbR-like gamma-butyrolactone binding regulator (SlbR) in S. coelicolor.