A novel shunt product was isolated from a disruptant of the actVI-ORFA gene involved in the biosynthesis of actinorhodin (ACT) in Streptomyces coelicolor A3(2). Its structure was elucidated as 1,4-naphthoquinone-8-hydroxy-3-[3(S)-acetoxy-butyric acid], (S)-NHAB, based on NMR, MS, and CD spectroscopic data as well as a single crystal X-ray crystallographic analysis. The formation of (S)-NHAB involves a retro-Claisen type C-C bond cleavage of an ACT biosynthetic intermediate. Feeding experiments with [1-13C] and [2-13C] acetates indicated its biosynthetic origin as a single octaketide chain. The relevant gene product, Act-ORFA, which is a functionally unknown protein, is proposed to play a regulatory role related to the multi-enzymatic steps to ACT production, based on the metabolic profile of its disruptant and the wide distribution of actVI-ORFA homologues in the gene clusters for Streptomyces aromatic polyketides. © 2003 Elsevier Ltd. All rights reserved.
|Translated title of the contribution||Structure and Biosynthesis Implication of (S)-NHAB, a Novel Shunt Product, from a Disruptant of the actVI-ORFA Gene for Actinorhodin Biosynthesis in Streptomyces coelicolor A3(2)|
|Number of pages||6|
|Publication status||Published - 27 Oct 2003|
Bibliographical notePublisher: Pergamon Elsevier Sci.Ltd
- Aromatic polyketides