Identification and characterization of the biosynthetic gene cluster of divergolides from Streptomyces sp. W112.

Divergolides are a group of structurally unprecedented ansamacrolactam antibiotics with antibacterial and antitumor activities. A biosynthetic gene cluster predicted to encode the biosynthesis of divergolides was cloned and sequenced from endophytic Streptomyces sp. W112. The gene cluster of divergolides (div) spans a DNA region of 61-kb and consists of 20 open reading frames (ORFs) that encode polyketide synthases (PKSs), enzymes for the synthesis of AHBA and PKS extender units, and post-PKS modifications, proposed regulators, and putative transporters. Disruption of the AHBA synthase gene (divK) completely abolished the production of divergolides proved its involvement in the biosynthesis of divergolides. Bioinformatics analysis suggested that the regulatory gene div8 in div gene cluster might encode a positive regulator for the biosynthesis of divergolides. Constitutive overexpression of div8 improved the production of divergolides E, implying that div gene cluster maybe responsible for the biosynthesis of divergolides. These findings set the stage for fully investigating the biosynthesis of divergolides and rational engineering of new divergolide analogs by genetic modifications, and pave the way to further improve the production of divergolides.