VEPES/XAS/DFT STUDIES OF ET SITES IN BIOINORGANIC CHEMISTRY

生物无机化学中 ET 位点的 VEPES/XAS/DFT 研究

• 批准号: 8362318
• 负责人: EDWARD I SOLOMON
• 金额: $ 0.58万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8362318
• 关键词: Bioinorganic Chemistry; Charge; Complex; Copper; Electron Transport; Electronics; Electrons; Funding; Grant; Heme; Ligands; Ligation; Metals; Modeling; Mononuclear; National Center for Research Resources; Principal Investigator; Radiation; Relaxation; Research; Research Infrastructure; Resources; Series; Site; Source; Spectrum Analysis; United States National Institutes of Health; Variant; cost; cytochrome c; electronic structure; ionization; meetings; oxidation; structural biology

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In studies performed during our previous proposals, we have been employing variable energy photoelectron spectroscopy in the valence and metal 2p regions to explore electronic relaxation, the change in electronic structure upon ionization of a reduced site. Thus far, this has been applied to Fe(SR)4 sites where the large electronic relaxation (ligand to M d CT) limits the charge change on oxidation and greatly reduces the geometry change (i.e. the reorganization energy of the site). We are now completing studies on a series of mononuclear Fe complexes in which we examined the effects of going from high to low spin and increased coordination number (tetrahedral vs. octahedral) as well as ligand variation to understand the contribution of heme ligation to electronic relaxation in the [Fetpp(imH)2] complex. We are now proposing to extend our PES studies of the bis-Im heme complex to the bis-met Fe(THT)2(tpp) complex and a cytochrome c model complex (Fe(C5-Im)(tpp)(THS).C6H6) where we will quantitate the effect of the met ligands on electronic relaxation and extend those results to electronic relaxation of cyt b vs. cyt c through DFT calculations and extended charge decomposition and valence bond configuration interaction analyses. In addition to PES studies of heme electron transfer sites, we will investigate covalency and electron delocalization and their contribution to electronic relaxation in blue copper, CuA, and Fe4S4 related model complexes.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 在我们之前的提案中进行的研究中，我们一直在价态和金属 2p 区域采用可变能量光电子能谱来探索电子弛豫，即还原位点电离时电子结构的变化。到目前为止，这已应用于 Fe(SR)4 位点，其中大的电子弛豫（M d CT 的配体）限制了氧化时的电荷变化，并大大降低了几何变化（即位点的重组能）。我们现在正在完成一系列单核 Fe 配合物的研究，其中我们检查了从高自旋到低自旋和增加的配位数（四面体与八面体）以及配体变化的影响，以了解血红素连接对电子弛豫的贡献在 [Fetpp(imH)2] 复合物中。我们现在提议将 bis-Im 血红素复合物的 PES 研究扩展到 bis-met Fe(THT)2(tpp) 复合物和细胞色素 c 模型复合物 (Fe(C5-Im)(tpp)(THS)。 C6H6），我们将定量met配体对电子弛豫的影响，并通过DFT计算和扩展电荷分解和价键将这些结果扩展到细胞色素b与细胞色素c的电子弛豫配置交互分析。除了血红素电子转移位点的 PES 研究之外，我们还将研究蓝铜、CuA 和 Fe4S4 相关模型复合物中的共价和电子离域及其对电子弛豫的贡献。