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，这些系统可以帮助阐明与血红素-铜氧化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（例如，细胞色素c氧化酶（CcO））和一氧化氮还原酶。 这些进化上相关的酶参与需氧和厌氧生物的生物能量学，并且共同具有血红素/M（M = Cu或非血红素Fe）活性位点，其分别还原性地切割分子氧（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活化，NO和氮氧化物化学和生物化学以及与环境中氮氧化物相关的问题提供基本见解。 主要的主题是合成离散血红素/M化合物，O2-化学还原血红素/铜组件，血红素/M配合物的配位化学，NO反应性研究，以及使用苯酚化学血红素/铜介导的O2-还原。 具体目标包括（1）使用血红素、轴向碱或Cu-配体的不同条件的血红素-O2-Cu（过氧）络合物的光谱和结构表征，（2）从单核组分组装的血红素/Cu/O2加合物的研究，（3）不同Fe-O2-Cu部分的反应性的系统比较，（4）血红素/M系统与μ-氧的配位化学的发展，μ-OH-和其它配体（例如，C1-，CN-）作为生物化学探针，（5）研究还原的血红素/M络合物及其CO和异氰化物加合物，（6）对产生一氧化二氮（N2 O）的NO还原酶模型系统进行彻底的研究和阐述，（7）产生新的血红素/Fe系统，该系统具有不同的Fe配体和三个N-供体和/或一个O-供体，（8）研究一氧化氮与这些和血红素/Cu系统的反应性，因为NO是CcO的可逆抑制剂，（9）在血红素/Cu组件的O2还原中使用酚作为电子-质子供体和Cu配体，和（10）探测与在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.