Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204, United States.
J Am Chem Soc. 2011 Feb 16;133(6):1971-7. doi: 10.1021/ja109226s. Epub 2011 Jan 19.
Reported is the structure and biosynthesis of ansalactam A, an ansamycin class polyketide produced by an unusual modification of the polyketide pathway. This new metabolite, produced by a marine sediment-derived bacterium of the genus Streptomyces , possesses a novel spiro γ-lactam moiety and a distinctive isobutyryl polyketide fragment observed for the first time in this class of natural products. The structure of ansalactam A was defined by spectroscopic methods including X-ray crystallographic analysis. Biosynthetic studies with stable isotopes further led to the discovery of a new, branched chain polyketide synthase extender unit derived from (E)-4-methyl-2-pentenoic acid for polyketide assembly observed for the first time in this class of natural products.
报道了 ansalactam A 的结构和生物合成，这是一种由聚酮途径的异常修饰产生的 ansamycin 类聚酮。这种新的代谢产物由海洋沉积物来源的链霉菌属细菌产生，具有新颖的螺环 γ-内酰胺部分和独特的异丁酰基聚酮片段，这在该类天然产物中是首次观察到。ansalactam A 的结构通过包括 X 射线晶体学分析在内的光谱方法确定。稳定同位素的生物合成研究进一步发现了一种新的支链聚酮合酶延伸单元，该单元来自（E）-4-甲基-2-戊烯酸，这在该类天然产物中是首次观察到。
