Cloning of the gene cluster responsible for the biosynthesis of brasilicardin a, a unique diterpenoid

Abstract

Brasilicardin A (BCA), produced by Nocardia brasiliensis IFM 0406 (currently referred to as N. terpenica), has a unique structure consisting of a diterpene skeleton with L-rhamnose, N-acetylglucosamine, amino acid, and 3-hydroxybenzoate moieties, and exhibits potent biological activities. To understand the biosynthetic machinery of this unique compound, we have cloned the corresponding gene cluster. Firstly, we cloned a gene by PCR that encodes geranylgeranyl diphosphate synthase (GGPPS), which produces a direct precursor of diterpene compounds. We obtained four candidate genes and one of the genes was confirmed to encode a GGPPS. By sequence analysis of regions flanking the GGPPS gene, we identified eleven genes (bra1-11), all oriented in the same direction. We did not, however, detect any genes related to L-rhamnose and N-acetylglucosamine biosyntheses in the flanking regions. A gene disruption experiment did indeed show that this gene cluster was responsible for BCA biosynthesis. © Japan Antibiotics Research Association.