O-O Bond Activation (and Formation) at Bimetallic Enzyme Active Sites

双金属酶活性位点的 O-O 键激活（和形成）

• 批准号: 10388098
• 负责人: LAWRENCE QUE
• 金额: $ 33.85万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10388098
• 关键词: Acquired Immunodeficiency Syndrome; Active Sites; Aldehydes; Anabolism; Antibiotics; Biochemical; Biomimetics; Cell Proliferation; Chlamydia trachomatis; Complex; DNA biosynthesis; Development; Dioxygen; Enzymes; Eukaryotic Cell; Eukaryotic Initiation Factors; Goals; Human; Hydrogen Bonding; Hydroxylation; Infection; Iron; Kinetics; Lead; Light; Malignant Neoplasms; Metabolic; Methane; Methane hydroxylase; Methods; Mixed Function Oxygenases; Modeling; Nature; Oxidants; Oxides; Oxygenases; Parasites; Production; Property; Reaction; Ribonucleotide Reductase; Role; Structure; Techniques; Toluene; Water; Work; carboxylate; deoxyhypusine monooxygenase; electronic structure; human pathogen; insight; novel therapeutics; oxidation; pathogenic bacteria; toluene-4-monooxygenase

The overall goal of this proposal is to understand how dioxygen is activated by nonheme diiron enzymes in metabolically critical transformations. These enzymes perform a remarkable range of functions, including the biosynthesis of DNA (ribonucleotide reductase (RNR)), the hydroxylation of organic substrates (soluble methane monooxygenase (sMMOH), toluene monooxygenase), the hydroxylation of the eukaryotic initiation factor 5a to regulate eukaryotic cell proliferation (human deoxyhypusine hydroxylase (hDOHH)), the biosynthesis of antibiotics (CmlA, CmlI), and the production of biodiesel (cyanobacterial aldehyde deformylating oxygenase (cADO)). Important project goals are to understand the roles of the initial diiron(II,III)- superoxo species and the subsequently formed diiron(III)-peroxo intermediates in substrate oxidation, how the latter can be converted to corresponding high-valent iron-oxo species that often serve as the key oxidants for substrate transformation, and to describe the structural, electronic, and reactivity properties of the high-valent intermediates. These goals will be accomplished by a combination of biochemical and biomimetic approaches. Our biochemical effort focuses on the diferric-peroxo intermediates (P) of hDOHH and CmlI we found to have different core structures from the carboxylate-bridged intermediates of sMMOH and RNR. With as many as four different P species to compare kinetically and spectroscopically, we aim to shed light on how these structural differences lead to the reactions their respective enzymes catalyze. Our biomimetic effort will focus on characterizing the various diiron-O2 intermediates listed above to gain detailed insight into their electronic structures and their oxidative reactivity. For example, can a diiron(II,III)-superoxo species hydroxylate toluene like toluene-4-monooxygenase? Is it possible for a diiron(III)- peroxo species oxidize C–H bonds to model a hydroxylase and also mimic the action of cADO in the oxidative deformylation of aldehydes? What factors favor one reaction over the other? Most importantly, how are diferric- peroxo intermediates converted into the high-valent diiron oxidants that carry out the most difficult substrate oxidations. These latter complexes are also critical to our efforts to clarify the nature of the high-valent diiron core in the methane-hydroxylating enzyme intermediate sMMOH-Q using new spectroscopic techniques. Our biomimetic efforts will be extended to the synthesis of Fe–O–Mn and Fe–O–Ce complexes. The Fe–O–Mn complexes mimic high-valent intermediates of the ribonucleotide reductase from the parasite Chlamydia trachomatis and the related R2lox enzymes found in pathogenic bacteria. Understanding the difference in the reactivity properties of high-valent FeFe and FeMn complexes may contribute to the development of better methods for treating infections from such human pathogens. The Fe–O–Ce complexes will help us understand the O–O bond formation mechanism of iron-catalyzed water oxidation by CeIV, which we propose to be just the reverse of the reaction sequence used by the diiron enzymes for dioxygen activation.

该提案的总体目标是了解如何通过非血红素迪隆激活二氧化物 代谢上关键转化的酶。这些酶执行了显着的功能， 包括DNA的生物合成（核糖核苷酸还原（RNR）），有机底物的羟基化 （可溶性甲烷单加氧酶（SMMOH），甲苯单加氧酶），真核生物的羟基化 起始因子5a调节真核细胞增殖（人脱氧蛋白羟化酶（HDOHH））， 抗生素（CMLA，CMLI）的生物合成和生物柴油的产生（蓝细菌醛 变形氧酶（CADO））。重要的项目目标是了解最初的二龙（II，iii）的作用 - 超氧物种和随后形成的diron（III） - 底物氧化中的过敏中间体，如何 后者可以转换为相应的高价值铁氧化物种，这些物种通常用作关键的氧化剂 底物转换，并描述高价值的结构，电子和反应性能 中间人。这些目标将通过生化和仿生方法的结合来实现。 我们发现，我们发现的HDOHH和CMLI的差异 - 过敏中间体（P）的焦点 与SMMOH和RNR的羧酸桥桥梁中间体具有不同的核心结构。和很多 作为四种不同的P物种可以在动力学和光谱上进行比较，我们的目的是阐明这些 结构差异导致其各自的酶催化的反应。 我们的仿生努力将着重于表征上面列出的各种Diiron-O2中间体 详细了解其电子结构及其氧化反应性。例如，可以 Diiron（II，III） - 甲苯甲苯甲苯甲苯甲苯 - 4-单氧化酶？二龙（iii）是否有可能 过氧物种将C – H键氧化以建模羟化酶，并模仿CADO在氧化中的作用 醛的变形？什么因素有利于一种反应？最重要的是，如何差异 过氧中间体转化为执行最困难底物的高价值透射氧化物 氧化物。这些后来的综合体对于我们阐明高价迪隆的性质的努力也至关重要 甲烷羟基化酶的核心使用新的光谱技术中间SMMOH-Q。 我们的仿生努力将扩展到Fe -O -MN和Fe -O -Ce络合物的合成。这 Fe – O-MN复合物模仿核糖核苷酸的高价值中间体从寄生虫还原 在致病细菌中发现的沙眼衣原体和相关的R2lox酶。了解 高价FEFE和FEMN复合物的反应性特性的差异可能有助于 开发更好的方法来治疗这种人类病原体的感染。 Fe – O -ce络合物 将帮助我们了解CEIV的铁催化水氧化的O – O键形成机制，这 我们建议仅是Diron酶用于二氧化激活的反应序列的逆向。