Identification of a novel shunt product produced by a disruptant of the actVI-ORFA gene involved in the biosynthesis of actinorhodin in Streptomyces coelicolor A3(2)

NMR and MS spectroscopy elucidated the structure of a novel shunt product isolated from a disruptant of the actVI-ORFA gene involved in the biosynthesis of actinorhodin (ACT) in Streptomyces coelicolor A3(2). The product, 1,4-naphthoquinone-8-hydroxy-3-[(3S)-acetoxybutyric acid], was found without complete abolition of ACT production, implying that the ORFA product might stabilise the multicomponent, type II PKS complex and perhaps assist the chemically spontaneous dehydration of a hemiketal intermediate for efficient pyran ring formation.