Identification and Characterization of the Cuevaene A Biosynthetic Gene Cluster in Streptomyces sp. LZ35

Graphical A choirmaster is found: An orphan gene cluster containing a chorismatase gene was indentified in Streptomyces sp. LZ35. Characterization showed it to be responsible for the biosynthesis of cuevaene A, a 3-HBA-derived polyketide that shows moderate antibacterial activity against Gram-positive bacteria. Genome sequence analysis of Streptomyces sp. LZ35 has revealed a large number of secondary metabolite pathways, including one encoded in an orphan type I polyketide synthase gene cluster that contains a putative chorismatase/3-hydroxybenzoate synthase gene. Mutagenesis and comparative metabolic profiling led to the identification of cuevaene A as the metabolic product of the gene cluster, thus making it the first 3-HBA containing polyketide biosynthetic gene cluster described to date. Cuv10 was proven to be responsible for the conversion of chorismate into 3-HBA; Cuv18 is speculated to be responsible for the 6-hydroxylation of 3-HBA during polyketide chain elongation. Additionally, several pathway-specific regulatory factors that affect the production of cuevaene A were identified. Our results indicate that targeted inactivation of a gene followed by comparative metabolic profiling is a useful approach to identify and characterize cryptic biosynthetic gene clusters.