Mechanisms of oxacycle- and olefin-installing iron/2-(oxo)glutarate oxygenases

 描述(由申请人提供)：人类铁(II)和2-(氧)戊二酸依赖(Fe/2OG)双加氧酶催化对中心生命过程(如代谢及其调控、转录、表观遗传)基本重要的反应中失活的脂肪碳中心的羟化，并与多种疾病相关。植物、真菌和细菌使Fe/2OG的结构和功能平台多样化，利用它进行一系列令人眼花缭乱的氧化转化，包括卤化、脱氢、环化和脂肪族碳中心的立体转化。由于产生大量重要天然产物药物的生物合成机制中充满了这样的Fe/2OG加氧酶，对反应机制和单个酶如何指导它们的预测了解可以使酶和途径的再利用成为量身定制的药物化合物。在最近在理解羟化、卤化和立体转化结果方面取得了很大进展后，我们将这个项目转向这个酶家族成员介导的两种最不为人所知的反应类型：氧环-安装1，3-和1，5-脱氢(草酰环化)和烯烃-安装1，2-脱氢(去饱和)反应，这些反应发生在抗生素克拉维酸和那普利霉素、麻醉剂东莨菪碱和杀虫剂降冰片灵的途径上。我们将阐明催化这些神秘反应的酶的结构和机制，以期对这个重要的酶家族的化学有一个完整的了解。

 DESCRIPTION (provided by applicant): Human iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) dioxygenases catalyze hydroxylation of inactivated aliphatic carbon centers in reactions that are fundamentally important to central life processes (e.g., metabolism and its regulation, transcription, epigenetic inheritance) and relevant to several diseases. Plant, fungi, and bacteria have diversified the Fe/2OG structural and functional platform, using it for a bewildering array of oxidative transformations that include halogenations, dehydrogenations, cyclizations and stereoinversions of aliphatic carbon centers. As the biosynthetic machinery generating a large number of important natural-product drugs are replete with such Fe/2OG oxygenases, a predictive understanding of the reaction mechanisms and how the individual enzymes direct them could enable re-purposing of the enzymes and pathways for tailor-made drug compounds. Having recently made great progress toward understanding the hydroxylation, halogenation, and stereoinversion outcomes, we turn in this project to two of the least well- understood reaction types mediated by members of this enzyme family: oxacycle-installing 1,3- and 1,5- dehydrogenation (oxacyclization) and olefin-installing 1,2-dehydrogenation (desaturation) reactions on the pathways to the antibiotics clavulanic acid and napthyridomycin, the anesthetic scopolamine, and insecticide, norloline. We will elucidate the structures and mechanisms of the enzymes catalyzing these enigmatic reactions to develop an integrated understanding of the chemistry of this important enzyme family.