Regio- and Stereoselective Intermolecular Oxidative Phenol Coupling in <i>Streptomyces</i>

Abstract

Intermolecular oxidative phenol coupling is the main process in nature for the formation of atropo­selective biaryl compounds. Although well defined in plants and fungi, this type of dimerization reaction in bacteria is poorly understood. Therefore, the biosynthesis of juli­chromes, specto­mycins, and setomi­mycin was investigated. The monomeric subunits of these biarylic pre-anthra­quinones are derived from a common polyketidic precursor, yet the coupling reaction proceeds in a regio­selective manner, with the position of attachment of the two subunits depending on the specific streptomycete strain. By using genome analysis and deletion experiments, the biosynthetic gene clusters were identified. Furthermore, it was established that cytochrome P450 enzymes are fundamentally involved during dimerization of the polyketide monomers