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

项目摘要/摘要： 该设备补充项目提案寻求资金购买冷喷雾电离 开展CSI-MS实验的质谱计，表征的有力途径 通常是不稳定的活性中间体。科学目标包括设计、合成和 研究有助于阐明结构基本方面的合成模型， 与铜和血红素/M(M=铜、铁)加工有关的M-配位、光谱和反应活性 分子氧(O2(G))和一氧化氮(NO(G))。令人担忧的铜蛋白包括赖氨酸 多糖单加氧酶、铜甲烷单加氧酶、 包括肽甘氨酸单加氧酶和双核铜蛋白NSPF。生化 研究提出了关于它们的活性部位的性质和机制的问题(S) 涉及O2(G)激活和C-H羟化的作用。LPMO可能是过氧酶，新的 PMMO研究表明，这是一个单一的铜活性中心，现在质疑的是，DBM和 PHM以铜激活O2，而不是以Cu2为中心。显然有必要进行合成和表征 铜(II)-氧基(CuII-O·)物种；它具有困难生物所需的氧化能力 底物。我们还计划阐明对O-O还原切割过程至关重要的基本原理 发生在处理O2的蛋白质中。此外，我们还将生成并表征这些结构， 新型高价双核铜(II)-氧-铜(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-铜活性部位， 其中O2-结合并被还原裂解，得到两个摩尔当量的水。人工合成的研究进展 模型有助于理解结构、O2-键、质子或氢键促进的O-O 裂解，以及活性部位苯酚的作用。建议进行调查，以便进一步调查 在血红素-过氧铜结构中O-O裂解的机制，其中，卟啉， 铁轴向配位体和铜配位体是系统变化的。各种有计划的方法 包括研究具有三个N-给体和一个附加苯酚的铜的新的络合物。 还将开展使用铜和血红素-M的(G)合成模型化学子项目。 对于铜络合物，重点将放在NO(G)还原偶联和机理研究上 关于NO(G)与金属的结合，N-N键的形成，可能是次亚硝酸盐N2O22- 中间体，以及质子和/或氢键对N-O裂解和N2O形成的贡献。 血红素/铁(或铜)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， 特别是对于二氧化碳，也将被研究为与生物活性相关。

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.