Discovery of an Antibacterial Isoindolinone-Containing Tetracyclic Polyketide by Cryptic Gene Activation and Characterization of Its Biosynthetic Gene Cluster.
Discovery of an Antibacterial Isoindolinone-Containing Tetracyclic Polyketide by Cryptic Gene Activation and Characterization of Its Biosynthetic Gene Cluster.
复制标题
DOI：
10.1021/acschembio.8b00553
复制
发表时间：
2018-08
影响因子：
4
通讯作者：
W. Thong;K. Shin‐ya;M. Nishiyama;T. Kuzuyama
中科院分区：
文献类型：
--
作者：
W. Thong;K. Shin‐ya;M. Nishiyama;T. Kuzuyama
天然产物筛选的主要挫折是含有新化学骨架的新型生物活性化合物的命中率下降。本文报道了异吲哚霉素（Idm）的鉴定和生物合成，这是一种前所未有的生物活性聚酮，具有新的含异吲哚酮的四环骨架。Idm是通过筛选利福平耐药（rif）突变体发现的，这些突变体是由本研究中使用的九种放线菌菌株产生的。在分离的114个rif突变体中，突变体S55-50-5过量产生Idm，而在野生型Streptomyces sp. SoC090715LN-16中几乎检测不到。硅分析结合基因缺失实验揭示了一个生物合成idmB基因簇，该基因簇负责Idm的产生。Idm的生物合成研究主要集中在其四环结构中五元环的形成以及甲基在核心结构上的附着。此外，使用独立腺苷化结构域（idmB21）进行的孔雀石绿磷酸盐测定表明，甘氨酸参与了含异吲哚酮骨架的形成。该研究有助于增加聚酮的结构多样性，并为理解一类新型四环聚酮的完整生物合成途径铺平了道路。
The major setback in natural product screening is the decreasing hit rate of novel bioactive compounds containing new chemical skeletons. Here we report the identification and biosynthesis of isoindolinomycin (Idm), an unprecedented bioactive polyketide with a novel isoindolinone-containing tetracyclic skeleton. Idm was discovered through the screening of rifampicin-resistant ( rif) mutants that were generated from nine actinomycete strains used in this study. Of the 114 rif mutants isolated, the mutant S55-50-5 was found to overproduce Idm, which is almost undetectable in the wild-type Streptomyces sp. SoC090715LN-16. An in silico analysis coupled with gene deletion experiments revealed a biosynthetic idmB gene cluster that is responsible for the production of Idm. The biosynthetic studies of Idm primarily focused on the formation of the five-membered ring in the tetracyclic structure and the attachment of the methyl group to the core structure. In addition, a malachite green phosphate assay performed using a stand-alone adenylation domain ( idmB21) demonstrated the involvement of glycine in the formation of the isoindolinone-containing skeleton. This study contributes to an increase in the structural diversity of polyketides and paves the way toward an understanding of the complete biosynthetic pathway of a novel class of tetracyclic polyketides.