Structural investigation of heteroyohimbine alkaloid synthesis reveals active site elements that control stereoselectivity.
Structural investigation of heteroyohimbine alkaloid synthesis reveals active site elements that control stereoselectivity.
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DOI：
10.1038/ncomms12116
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发表时间：
2016-07-15
影响因子：
16.6
通讯作者：
O'Connor SE
中科院分区：
文献类型：
--
作者：
Stavrinides A;Tatsis EC;Caputi L;Foureau E;Stevenson CE;Lawson DM;Courdavault V;O'Connor SE
植物产生大量的生物活性代谢物，通常在同一分子支架上具有立体化学变化。立体化学的这些变化极大地影响了生物活性。值得注意的是，异育亨宾生物碱的立体异构体显示出不同的药理活性。我们报道了长春花中的一种中链脱氢/还原酶(MDR)，它能催化异育亨宾异构体的形成。在这里，我们报告了额外的异育亨宾合成酶(HYS)的发现，其中一个产生了非对映异构体的混合物。解决了三个HYS的晶体结构，提供了对反应性和立体选择性的机理的洞察，一个环的突变改变了产物的特异性。定位和基因沉默实验为了解这些酶在体内的功能提供了基础。这项工作为探索MDR如何在专门的植物代谢中进化产生结构和生物多样性奠定了基础，并为基于这一支架的新化合物的代谢工程打开了可能性。植物异育亨宾生物碱的立体化学是决定其不同生物活性的关键因素。在这里，作者进行了结构、定位和遗传学实验，以了解三种异育亨宾合成酶的立体选择性机制，并确定它们在体内的功能。
Plants produce an enormous array of biologically active metabolites, often with stereochemical variations on the same molecular scaffold. These changes in stereochemistry dramatically impact biological activity. Notably, the stereoisomers of the heteroyohimbine alkaloids show diverse pharmacological activities. We reported a medium chain dehydrogenase/reductase (MDR) from Catharanthus roseus that catalyses formation of a heteroyohimbine isomer. Here we report the discovery of additional heteroyohimbine synthases (HYSs), one of which produces a mixture of diastereomers. The crystal structures for three HYSs have been solved, providing insight into the mechanism of reactivity and stereoselectivity, with mutation of one loop transforming product specificity. Localization and gene silencing experiments provide a basis for understanding the function of these enzymes in vivo. This work sets the stage to explore how MDRs evolved to generate structural and biological diversity in specialized plant metabolism and opens the possibility for metabolic engineering of new compounds based on this scaffold. The stereochemistry of the plant heteroyohimbine alkaloids is a key factor determining their diverse biological activities. Here, the authors carry out structural, localization and genetic experiments to understand the mechanism of stereoselectivity for three heteroyohimbine synthases and to identify their function in vivo.