Effects of Two Putative LacI-family Transcriptional Regulators, SCO4158 and SCO7554, on Antibiotic Pigment Production of Streptomyces coelicolor and Streptomyces lividans

Streptomycetes produce many secondary metabolites, including antibiotics, antifungal agents, anti-parasitic drugs, and immune suppressors. Evaluation of streptomycetes, Streptomyces coelicolor and Streptomyces lividans, was carried out as research models. Overexpression of the putative Lad-family transcriptional regulator SCO4158 enhanced the production of antibiotic pigments in S. coelicolor but decreased their production in S. lividans, which serves as an example of discrepancy between two closely related strains. The comparison of biological mechanisms of the SCO4158 protein between these two strains represents a potential approach for the identification of S. coelicolor and S. lividans genes involved in antibiotic pigment production. Overexpression of the putative Lad-family transcriptional regulator SCO7554 either decreased (homologous gene from the same overexpression strain) or enhanced (heterologous gene from the other strain) antibiotic pigment production by the homologous SCO7554. The SCO7554 genes in S. coelicolor and S. lividans differ by only two codon changes, neither of which alters the amino acid sequence; hence, our result suggests a role in protein synthesis for SCO7554. Codon usage by SCO7554 is, therefore, critical for its biological function on antibiotic pigment production.