The role of geometric structure in avoidance of oxygen rebound to enable aliphatic halogenation and oxacyclization by non-heme Fe(IV)-oxo (ferryl) complexes

项目摘要/摘要 依赖铁(II)和2-(氧)戊二酸(Fe/2OG)的加氧酶催化羟化，卤化， 脂肪族碳中心的环化、脱氢、立体转化、C-H键活化反应 它们共同代表着合成化学的圣杯。重要的天然生物合成途径-- 产品药物中充满了这些酶，制药业开始利用 进化的Fe/2OG加氧酶作为生物催化剂，用于合成药物的“绿色”过程。近期 宾夕法尼亚州立大学对Fe/2OG羟基酶、卤代酶和环化酶的研究表明， 底物相对于常见的铁(IV)-氧代(铁基)和铁(III)-羟基/底物-自由基 中间体可能是控制反应结果的关键。根据目前已有的数据，我们 假设金属辅因子的结构重排而不是底物位置是 指导区域选择性的主要因素。因此，在这项工作中，我们将进行光谱表征 忠实的反应态类似物，以获得关于单个酶如何调整结构的第一手见解 并揭示了在Fe/2OG超家族中指导反应的常见模式 加氧酶。在这个项目中，我们将创新和部署一套新型的中间体模拟和光谱 用于解析与药物相关的关键中间态的几何构型的探针/方法 Fe/2OG酶亚类。我们对辅因子结构和相对配置的解释 底物决定了不同的结果将有助于努力发现这个超家族的新成员 指定它们的表型。最终，在这个项目中获得的信息将有助于开发新的 用于药物合成的生物催化剂。

Project Summary/Abstract Iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases catalyze hydroxylation, halogenation, cyclization, dehydrogenation, and stereoinversion of aliphatic carbon centers, C–H-bond-activation reactions that collectively represent a holy grail of synthetic chemistry. Biosynthetic pathways to important natural- product drugs are replete with these enzymes, and the pharmaceutical industry is beginning to leverage evolved versions of Fe/2OG oxygenases as biocatalysts for "green" processes to their synthetic drugs. Recent studies of Fe/2OG hydroxylases, halogenases and cyclases by the Penn State group show that the disposition of the substrate relative to the common iron(IV)-oxo (ferryl) and iron(III)-hydroxo/substrate-radical intermediates may be crucial for control of reaction outcome. On the basis of data available so far, we hypothesize that the structural rearrangement of the metallocofactor rather than the substrate positioning is the primary factor directing regioselectivity. Therefore, in this work, we will perform spectroscopic characterization of faithful reactive-state analogs to gain first-hand insight as to how the individual enzymes adjust the structure of the active complex and to uncover common modes that direct reactivities in the superfamily of Fe/2OG oxygenases. In this project, we will innovate and deploy a suite of novel intermediate mimics and spectroscopic probes/methodologies to resolve the geometries of the key intermediate states in the pharmaceutically relevant subclasses of Fe/2OG enzymes. Our elucidation of how the cofactor structures and relative dispositions of the substrates dictate the divergent outcomes will inform efforts to discover novel members of this superfamily and assign their phenotypes. Ultimately, information obtained in this project will be instrumental in developing new biocatalysts for drug synthesis.