Isolation and characterization of bamA genes, homologues of the γ-butyrolactone autoregulator-receptor gene in Amycolatopsis mediterranei, a rifamycin producer

Abstract

Four genes (bamA1, bamA2, bamA3 and bamA4) encoding homologues of the gamma-butyrolactone autoregulator receptor of Streptomyces were found and cloned from Amycolatopsis mediterranei, a typical non-Streptomyces actinomycetes and a producer of rifamycin, one of the major anti-tuberculosis drugs in clinical treatment. Transcriptional analysis demonstrated that bamA1 and bamA2 are transcribed in a growth-dependent manner, while bamA3 and bamA4 are constitutively transcribed during growth. Binding assays using (3)H-labeled autoregulator analogues as ligands confirmed that all of the recombinant BamA proteins expressed in Escherichia coli have clear binding activity toward several types of Streptomyces autoregulators. The ligand specificity of the recombinant BamA1 protein was identical to that of the crude cell-free lysates of A. mediterranei reported in our previous work. These results suggest that A. mediterranei, which is phylogenetically situated in a distal clade from the genus Streptomyces as non-Streptomyces actinomycetes, has an autoregulator-mediated signaling system.

Renewed interests in the discovery of bioactive actinomycete metabolites driven by emerging technologies

“…SE50/110. Regulations of rifamycin production in Amycolatopsis mediterranei by bamA genes-homologues of γ-butyrolactone autoregulator genes-were characterized through transcriptome analysis (Aroonsri et al 2008).…”

Molecular characterization of a Rhodococcus jostii RHA1 γ-butyrolactone(-like) signalling molecule and its main biosynthesis gene gblA

“…The enzymes involved in the biosynthesis of γ-butyrolactones have been described and partially characterized in several Streptomyces strains. They have been named according to the species that employ them or the compound that is regulated by these molecules 15 – 17 , 19 , 26 , 27 . For unification purposes, we have renamed these enzymes so that they can be applied to any butanolide system in any strain by employing the nomenclature Gbl ( g amma- b utyro l actone) (Table 1 ).…”

Regulation of antibiotic production in Actinobacteria: new perspectives from the post-genomic era

“…The strains A. mediterranei and M. echinospora produce a GBL similar to IM62, derived from S. lavendulae (see section 9.2)369 . In the rifamycin producer A. mediterranei, four genes that encode GBL6receptor paralogues are present, namely bamA1$bamA4371 . All four receptor proteins can bind GBLs derived from Streptomyces, including VB from S. virginiae and SCB1 from S. coelicolor.…”

“…All four receptor proteins can bind GBLs derived from Streptomyces, including VB from S. virginiae and SCB1 from S. coelicolor. Only BamA1 was shown to bind the IM62 GBL , an autoregulator produced by A. mediterranei itself369,371 .Kitasatospora setae, a member of a genus closely related to Streptomyces, harbours several GBL6receptors264,372 . K. setae produces bafilomycins A1 and B1.…”