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

项目总结/摘要 铁（II）-和2-（氧代）戊二酸依赖性（Fe/2 OG）加氧酶催化羟基化、卤化 环化、脱氢和脂肪族碳中心的立体转化、C-H键活化反应 它们共同代表了合成化学的圣杯。生物合成途径重要的天然- 产品药物充满了这些酶，制药行业开始利用这些酶， Fe/2 OG加氧酶作为生物催化剂用于“绿色”过程以合成药物。最近 宾夕法尼亚州立大学研究组对Fe/2 OG羟化酶、卤化酶和环化酶的研究表明， 相对于常见的铁（IV）-氧代（铁酰基）和铁（III）-羟基/底物自由基 中间体对于控制反应结果可能至关重要。根据目前掌握的数据，我们 假设金属辅因子的结构重排而不是底物定位是 主要因素指导区域选择性。因此，在这项工作中，我们将进行光谱表征 忠实的反应状态类似物，以获得关于单个酶如何调节结构的第一手见解 并揭示了Fe/2 OG超家族中直接反应的共同模式 加氧酶。在这个项目中，我们将创新和部署一套新的中间模拟物和光谱 探针/方法学，以解决药物相关的关键中间状态的几何形状 Fe/2 OG酶的亚类。我们阐明了如何辅因子的结构和相对处置的 底物决定了不同的结果将为发现这个超家族的新成员的努力提供信息， 分配它们的表型。最终，在该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.