ELECTRONIC STRUCTURE OF FE-OXO AND MN-OXO COMPLEXES

这个提议涉及到量子力学的使用， 计算和随后的分析，以检查电子 双核和多核Fe-O配合物及Mn-O结构 配合物作为金属蛋白活性中心的相关模型 系统. Fe-O络合物存在于：（a）核糖核苷酸 还原酶，（B）甲烷单加氧酶，（c）紫酸 磷酸酶，和（d）血红蛋白。 一种多核Mn-O配合物 发生在氧释放复合物的活性位点， 光系统II 我们所有的计算都是关于X α或局部自旋的 密度自洽场型 我们将系统地研究 作为氧化态的函数的相关模型络合物， 配位几何结构和底物配体的结合，或 反应中间体 计算结果将与 实验结果的磁化率，并通过 穆斯堡尔、电子自旋共振和/或光学光谱 用于蛋白质和合成类似物。 此外，我们将研究 电子密度分布和自旋密度分布 因为这些特征应该紧密相关， 催化机制。 定性定量配体 结合能学也将被探索。 我们的目标是 预测和实验性质，以及获得洞察力 催化功能和调节这些酶。

This proposal involves the use of quantum mechanical calculations and subsequent analysis to examine the electronic structure of dinuclear and polynuclear Fe-O complexes and Mn-O complexes as relevant models for active sites of metalloprotein systems. Fe-O complexes are found in: (a) ribonucleotide reductase, (b) methane monooxygenase, (c) purple acid phosphatases,and (d) hemerythrin. A polynuclear Mn-O complex occurs at the active site in the oxygen evolving complex of photosystem II. All of our calculations will be of the Xalpha or local spin density self consistent field type. We will systematically study relevant model complexes as a function of oxidation state, coordination geometry, and binding of substrate ligands or reaction intermediates. The calculations will be compared with experimental results by magnetic susceptibility, and by Mossbauer, electron spin resonance and/or optical spectroscopies for proteins and synthetic analogues. Further, we will examine electron density distributions and spin density distributions in some detail since these features should be closely associated with catalytic mechanism. Qualitative and quantitative ligand binding energetics will also be explored. Our goal is to relate predicted and experimental properties as well as to gain insight into catalytic function and regulation in these enzymes.