Redox Reactions of the AdoMet Radical Enzyme Superfamily

AdoMet 自由基酶超家族的氧化还原反应

• 批准号: 9329461
• 负责人: SEAN J ELLIOTT
• 金额: $ 31.67万
• 依托单位: BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9329461
• 关键词: Active Sites; Address; Amino Acids; Anabolism; Behavior; Binding; Binding Proteins; Bioinformatics; Biological; Biological Models; Chemicals; Chemistry; Cobalamin; Coenzymes; Complex; Coupled; Couples; Coupling; Data; Electrochemistry; Electron Transport; Electrons; Elements; Enzymatic Biochemistry; Enzymes; Family; Family member; Film; Generations; Goals; Health; Heart; Human; Investigation; Iron; Knowledge; Measurement; Measures; Methods; Methylation; Modification; Molecular; Natural Products; Nature; Nucleic Acids; Oxidation-Reduction; Pathway interactions; Pharmaceutical Preparations; Play; Process; Production; Property; Prosthesis; Proteins; Protons; Reaction; Reporting; Role; S-Adenosylmethionine; Series; Site; Sulfur; Thermodynamics; Time; Ursidae Family; Work; cofactor; enzyme biosynthesis; enzyme model; experience; insight; member; mutant; oxidation; repaired; small molecule; structural biology; tool

PROJECT SUMMARY The AdoMet Radical Enzyme (ARE) superfamily catalyzes a wide array of chemical transformations that span sulfur-insertion, isomerization, activation of glycyl-radical enzymes, metallo-cofactor biosynthesis, methylations, oxidations and desaturations. All of these reactions are initiated by similar components: AREs are marked by an active-site amino acid signature of CX3CX2C (which binds a unique [Fe4S4] cluster) and structural elements that bind the required co-factor (or co-substrate) S-Adenosyl-methioning (AdoMet). In all cases, the chemistry of AREs is thought to start with the reductive cleavage of AdoMet by the active site cluster, resulting in a 5'-dA· radical that is used in the many, many different chemical transformations listed above. AREs are indeed a superfamily with over 105 distinct members, and recent bioinformatics analyses have addressed ~50,000 sequences, helping to categorize their reactivity in many distinct biological roles/pathways involving the synthesis of small molecules, complex natural products, and protein and nucleic modifications. Further complexity within the ARE superfamily can be found in how many family members have yet-another redox cofactor, either one or two additional `auxiliary' [Fe4S4] clusters, or cobalamin. Together, the catalytic and cofactor diversity of the ARE superfamily articulate how very little we understand about the molecular details that guide the reactivity of AREs, we not only do not understand why different AREs do different reactions, there is little data on the redox properties of ARE family members, which is essential to understand how they can achieve the chemistry that they do. We propose to address that knowledge gap. We have have been recently successful in utilizing the crystallographically-characterized ARE BtrN as a model system for examining the redox potentials of the AdoMet-binding active site ([Fe4S4]Ado) and the BtrN auxiliary cluster ([Fe4S4]Aux) using our unique experience in protein film electrochemistry. Here, we propose to (i) use BtrN as a model system to allow for the systematic assessment of what controls the redox potentials and proton-coupled nature of the active site, (ii) expand our work on BtrN to other AREs that contain additional FeS clusters, allowing for the first direct comparison of redox properties between AREs, and (iii) examine the redox chemistry of cobalamin-containing AREs, in order to further develop protein electrochemistry as a tool for redox enzymology in the ARE superfamily.

项目摘要 Adomet自由基酶（IS）超家族催化了跨越广泛的化学转化 硫插入，异构化，糖基 - 激活酶的激活，金属伴侣生物合成， 甲基化，氧化和去饱和。所有这些反应都是由类似组成部分启动的：ARES 由CX3CX2C的活性位点氨基酸特征（结合唯一[Fe4S4]群集）和 结合所需的共同因素（或共覆盖）S-腺苷 - 甲酸化（ADOMET）的结构元素。总的来说 案例，ARES的化学被认为是从活跃部位减少ADOMET的裂解开始 群集，导致5'-da·激进的列出的许多不同的化学转化中使用 多于。 Ares确实是一个超过105个不同成员的超家族，并且最近的生物信息学分析 已经解决了约50,000个序列，有助于将其反应性分类为许多不同的生物学 涉及小分子，复杂天然产物以及蛋白质和核的角色/途径 修改。在有多少家庭成员中可以找到超级家族的进一步复杂性 另一个是氧化还原辅助因子，即另外一个或两个“辅助” [Fe4S4]簇或钴胺素。在一起， 超家族的催化和辅因子多样性我们对此有多了解 指导Ares反应性的分子细节，我们不仅不了解为什么不同的Ares这样做 不同的反应，关于家庭成员的氧化还原特性的数据很少，这对于 了解他们如何实现自己所做的化学反应。我们建议解决这一知识差距。我们 最近在使用晶体学特征化的是BTRN作为模型 检查ADOMET结合活性位点（[FE4S4] ADO）和BTRN辅助部位的氧化还原电势的系统 使用我们在蛋白质膜电化学方面的独特经验的聚类（[FE4S4] AUX）。在这里，我们建议（i）使用 BTRN作为模型系统，允许系统地评估控制氧化还原电位和 活性位点的质子耦合性质，（ii）将我们在BTRN上的工作扩展到包含其他FES的其他ARE 集群，允许首次直接比较ARES之间的氧化还原性能，（iii）检查氧化还原 为了进一步发展蛋白质电化学作为氧化还原的工具，含钴胺素的化学 酶学中的酶学是超家族。