Reactivity-Activation of O(2) or NO in Copper and Heme-Cu Coordination Complexes

项目概要/摘要： 本设备补充项目建议书寻求资金，以购买一台冷喷雾电离 质谱仪进行CSI-MS实验，一个强大的方法来表征 通常是不稳定的活性中间体。科学目标包括设计、合成和 研究合成模型，这将有助于阐明结构的基本方面， 与铜和血红素/M（M = Cu，Fe）加工相关的M-连接、光谱和反应性 分子氧（O2（g））和一氧化氮（NO（g））。关注的铜蛋白质包括溶解性的 多糖单加氧酶，Cu-甲烷单加氧酶， 包括肽基甘氨酸单加氧酶和双核铜蛋白NspF。生化 研究提出了关于其活性部位的性质和作用机制的问题 涉及O2（g）活化和C-H羟基化的作用。LPMO可能是过氧合酶，新的 pMMO研究表明单Cu活性位点，现在质疑DBM和 PHM以Cu中心激活O2，而以Cu 2中心激活O2。显然需要综合和描述 铜（II）-氧（CuII-O·）物种;它具有难以生物降解所需的氧化能力， 印刷受体.我们还计划阐明O-O还原裂解过程的关键基础 存在于处理氧气的蛋白质中此外，我们将生成和表征结构， 新型高价双核Cu（II）-O-Cu（III）配合物的物理性质和反应活性。 拟议的研究还将集中在细胞色素c氧化酶的血红素铜活性位点， 其中O2-结合并被还原裂解以产生两摩尔当量的水。合成的研究 模型有助于理解结构，O2结合，质子或氢键促进O-O 裂解，以及活性位点苯酚的作用。建议进一步调查 血红素-过氧-铜结构中O-O断裂的机制，其中卟啉， Fe轴向配体和铜配体系统地变化。各种计划方法 包括研究具有三个N-供体和附加酚铜的新螯合物。 还将开展含铜和血红素-M的NO（g）合成模型化学次级项目。 对于Cu配合物，重点将是NO（g）还原偶联，并研究其机理 与NO（g）金属结合有关，形成N-N键，得到推定的次硝酸根N2 O22- 中间体，以及质子和/或氢键对N-O裂解和N2 O形成的贡献。 血红素/Fe（或Cu）介导的NO（g）偶联在NO还原酶和合成模型中是关键的。 将对这一过程进行调查。金属-过氧亚硝酸盐（PN，来自金属离子+ O2（g）+ NO（g））反应性， 特别是对二氧化碳的影响，也将作为与生物活性相关的研究。

Project Summary/Abstract: This equipment supplement project proposal seeks funds to purchase a Cold-Spray Ionization Mass Spectrometer to carry out CSI-MS experiments, a powerful approach to characterizing typically unstable reactive intermediates. The scientific objectives include the design, synthesis & investigation of synthetic models which will aid the elucidation of fundamental aspects of structure, M-ligation, spectroscopy and reactivity relevant to copper and heme/M (M = Cu, Fe) processing of molecular oxygen (O2(g)) and nitric oxide (NO(g)). Copper proteins of concern include lytic polysaccharide monooxygenases, Cu-methane monooxygenases, the enzyme family which includes peptidylglycine monooxygenase, and a binuclear copper protein, NspF. Biochemical research has raised questions concerning the nature of their active sites and the mechanism(s) of action involving O2(g) activation and C-H hydroxylation. LPMOs may be peroxygenases, new pMMO studies suggest a mono-Cu active site, and it is now questioned as to whether DBM and PHM activate O2 with a Cu vs a Cu2 center. There are clear needs to synthesize and characterize the copper(II)-oxyl (CuII-O·) species; it has the oxidizing ability needed for the difficult biological substrates. We also plan to elucidate fundamentals critical to the O-O reductive cleavage process occurring in proteins which process O2. Also, we will generate and characterize the structures, physical properties and reactivity of new high-valent binuclear Cu(II)-O-Cu(III) complexes. Proposed research will also focus on the heme-copper active site of cytochrome c oxidases, where O2-binds and is reductively cleaved to give two mole-equiv water. The study of synthetic models aids an understanding of structure, O2-binding, proton or H-bonding facilitated O-O cleavage, and the role of the active-site phenol. Investigations are proposed to further investigate the mechanisms of O-O cleavage in heme-peroxo-copper constructs, where the porphyrinate, the Fe axial ligand and the copper ligand are systematically varied. A variety of planned approaches include study of new chelates for copper which possess three N-donors and an appended phenol. NO(g) synthetic model chemistry sub-projects with copper and heme-M will also be carried out. With Cu complexes, the focus will be on NO(g) reductive coupling, and study of mechanisms pertaining to the NO(g) metal-binding, formation of the N–N bond giving putative hyponitrite N2O22– intermediates, and proton and/or H-bonding contributions to N–O cleavage and N2O formation. Heme/Fe (or Cu) mediated NO(g) coupling is critical in NO-Reductases and synthetic models for this process will be investigated. Metal-peroxynitrite (PN, from metal ion + O2(g) + NO(g)) reactivity, especially toward CO2, will also be studied as relevant to biological activity.