HEME/COPPER AND HEME/NONHEME IRON O2 AND NO REACTIVITY

长期研究目标是设计、合成和研究模型化合物系统，有助于阐明与血红素铜氧化酶（例如细胞色素 c 氧化酶 (CcOs)）和一氧化氮还原酶所利用的化学相关的结构、金属连接、光谱学和反应性的基本方面。 这些进化相关的酶参与需氧和厌氧生物体的生物能学，并且共同具有血红素/M（M = Cu 或非血红素 Fe）活性位点，分别还原性裂解双氧 (OZ) 或一氧化氮 (NO)。 该研究有助于更好地了解酶的结构和机制，并为生物 O2 激活、NO 和氮氧化物化学和生物化学以及环境中氮氧化物相关问题提供基本见解。 主要主题是离散血红素/M 化合物的合成、还原血红素/铜组装体的 O2 化学、血红素/M 复合物的配位化学、NO 反应性研究以及苯酚化学在血红素/铜介导的 O2 还原中的应用。 具体目标包括 (1) 使用不同条件的血红素、轴碱或铜配体对血红素-O2-Cu（过氧）复合物进行光谱和结构表征，(2) 研究由单核成分组装的血红素/Cu/O2 加合物，(3) 不同 Fe-O2-Cu 部分的反应性的系统比较，(4) 开发血红素/M 系统与 mu-oxo、mu-OH- 和其他配体的配位化学（例如，C1-，CN-）作为生化探针，（5）还原血红素/M复合物及其CO和异氰化物加合物的研究，（6）对产生一氧化二氮（N2O）的NO还原酶模型系统进行彻底研究和阐述，（7）生成具有不同铁配体的新血红素/铁系统，具有三个N-供体和/或一个O-供体，（8）一氧化氮反应性研究与这些和血红素/铜系统，因为NO是CcO的可逆抑制剂，（9）使用酚作为电子-质子供体和铜配体，在血红素/铜组装体的O2还原中，以及（10）探索与CcO中发现的咪唑-苯酚（His-Tyr）共价键的形成和功能相关的化学。

The long-term research objective is to design, synthesize and investigate model compound systems which can help elucidate fundamental aspects of structure, metal-ligation, spectroscopy and reactivity relevant to the chemistry utilized by heme-copper oxidases (e.g., cytochrome c oxidases (CcOs)) and nitric oxide reductases. These evolutionarily related enzymes are involved in the bioenergetics of aerobic and anaerobic organisms, and have in common a heme/M (M = Cu or non-heme Fe) active site which reductively cleaves dioxygen (OZ) or nitric oxide (NO), respectively. The research can contribute to a better understanding of enzyme structure and mechanism, and provide fundamental insights into biological O2-activation, NO and nitrogen oxide chemistry and biochemistry, and issues related to nitrogen oxides in the environment. Major themes are the synthesis of discrete heme/M compounds, O2-chemistry of reduced heme/Cu assemblies, the coordination chemistry of heme/M complexes, NO reactivity studies, and use of phenol chemistry in heme/Cu mediated O2-reduction. Specific aims include (1) spectroscopic and structural characterization of heme-O2-Cu (peroxo) complexes using varied conditions of heme, axial base, or Cu-ligand, (2) study of heme/Cu/O2 adducts assembled from mononuclear components, (3) systematic comparisons of the reactivity of varying Fe-O2-Cu moieties, (4) development of the coordination chemistry of heme/M systems with mu-oxo, mu-OH- and other ligands (e.g., C1-, CN-) of interest as biochemical probes, (5) study of reduced heme/M complexes and their CO and isocyanide adducts, (6) thorough investigation and elaboration upon a NO reductase model system which produces nitrous oxide (N2O), (7) generation of new heme/Fe systems having varied Fe-ligands with three N-donors and/or with one O-donor, (8) study of nitric oxide reactivity with these and heme/Cu systems, since NO is a reversible inhibitor of CcO, (9) use of phenols as electron-proton donors and Cu-ligands in O2-reduction with heme/Cu assemblies, and (10) probing of the chemistry relevant to formation and function of an imidazole-phenol (His-Tyr) covalent link found in CcO.