Biosynthesis of the polyether antibiotic monensin A: incorporation of a polyketide chain elongation intermediate

Abstract

Evidence that the polyether antibiotic monensin A is constructed by a processive strategy of polyketide assembly has been obtained by the specific incorporation of labelled 5-oxo-2,4-dimethylhexanoate, activated as an acetylcysteamine thioester, into the antibiotic in shake cultures of Streptomyces cinnamonensis: crucial to the successful incorporation are the presence of 2,6-O-dimethyl-β-cyclodextrin and a β-oxidation inhibitor during the fermentation.