海洋链霉菌中P450酶参与催化吲哚咔唑化合物形成的新颖分子机制

吲哚咔唑化合物（Indolocarbazoles，ICZs）能够通过拓扑异构酶、细胞信号转导通路中各种激酶以及细胞周期调控因子来实现多靶点抑制肿瘤生长，具有良好的临床开发前景。分离自我国三亚红树林的海洋链霉菌新种Streptomyces sanyensis FMA能产生分别含有1’, 5’-双苷化和1’, 3’-双苷化糖环的ICZs化合物星孢菌素（Staurosporine）和Streptocarbazole。本项目拟以链霉菌FMA为研究材料，（1）阐明P450催化星孢菌素中C5’-N12键形成的新颖生化反应机理，（2）从基因组中挖掘新的催化Streptocarbazole中C3’-N12键形成的新的P450，揭示酶催化反应的特性与新颖性，解析两个P450酶区域选择性地催化C-N键形成的新颖酶学分子机制，拓宽酶的底物特异性，为开展化合物结构多样性研究提供重要的工具酶和可靠的理论指导。

The indolocarbazole compounds (ICZs) have been found to be potential multi-targeted anticancer clinical candidates through inhibitions against topoisomerases, protein kinases in cellular signal transduction pathways, as well as cell cycle regulatory factors. Streptomyces sanyensis FMA, isolated from a mangrove soil sample collected in Sanya, China, is capable to produce a series of ICZs, including Staurosporine bearing a cyclic N-glycosidic linkage between the 1’, 5’-carbons of the glycosyl moiety and the 12,13-nitrogens of the indolocarbazole ring, and Streptocarbazole possessing an exceptional cyclic N-glycosidic linkage between the 1’, 3’-carbons and the 12,13-nitrogens. In this project, on the one hand we are going to elucidate the pending enzymatic mechanism of C5’-N13 bond formation in Staurosporine catalyzed by P450 monooxygenase; on the other hand, we plan to uncover new P450 enzyme involved in C3’-N12 bond formation in Streptocarbazole. We will explore the molecular mechanism of the P450s-catalyzed C-N formation in depth, disclose their enzymatic properties and novelties, and demonstrate the regioselectivity of the two P450s. Our study will provide novel tool enzymes and reliable theoretical guidance for diversification of ICZs structures.