S K-EDGE XAS STUDIES AS A PROBE OF ELECTRONIC STRUCTURE/CONTRIBUTION TO FUNCTION

SK-EDGE XAS 研究作为电子结构/功能贡献的探针

• 批准号: 8362398
• 负责人: BRITT HEDMAN
• 金额: $ 0.03万
• 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/8362398
• 关键词: Active Sites; Biochemical Reaction; Complex; DNA glycosylase; Electrons; Enzymes; Escherichia coli; Family; Ferredoxin; Funding; Grant; Hydrogen Bonding; Iron; Ligands; Lyase; Metals; Methodology; Modeling; Mono-S; Mutation; National Center for Research Resources; Principal Investigator; Protein Binding; Pyruvate; Radiation; Research; Research Infrastructure; Resources; Series; Site; Solvents; Source; Spectrum Analysis; Structure; Sulfur; System; United States National Institutes of Health; cost; desaturase; dimethyl sulfoxide reductase; electronic structure; enzyme model; protein complex; structural biology; sulfite oxidase

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. Ligand K-edge XAS provides a direct probe of ligand metal bonding. We have developed this methodology to investigate the electronic structures of model complexes and protein active-sites of a number of clusters and sites, in particular Fe-S, Cu-S clusters and dithiolene-containing Mo/W sites. In the previous proposal period, among several studies, we evaluated the generality of the difference between HiPIPs and ferredoxins and systematically studied the effect of H-bonding, solvent interaction and effect of changing dielectric field around these and other clusters using well-characterized model complexes and proteins, and combined experimental results with DFT calculation. We have also developed the bonding/geometric structure correlations in the Mo(tris)dithiolenes and the mechanism of oxo trasnsfer in the DMSO reductase family of enzymes and models. In this proposal we plan to extend this methodology, and combine it with complementary spectroscopies, to study several Fe-S systems, such as the interaction of SAM with the Fe4S4 cluster in pyruvate lyase activating enzyme; MutY - a DNA glycosylase from Escherichia coli; Fe2S2 protein binding to ?9 desaturase; and effects of Cys->Ser mutations on electron delocalization in iron sulfur clusters. We also intend to study a series of Mo mono- and bis-oxo bis(dithiolene) complexes that model the states of the sulfite oxidase family. The specific aim is to define the electronic structure of enzymes and model complexes and understand the correlations between structure and function of enzymatic reactions.

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 配体K-EDGE XAS为配体金属键合提供了直接的探针。我们发展了这种方法来研究模型络合物的电子结构以及一些团簇和中心的蛋白质活性中心，特别是Fe-S，Cu-S团簇和含二硫杂环的Mo/W中心。在前期的研究中，我们评估了HIPIPs和铁氧还蛋白差异的普遍性，并利用表征良好的模型络合物和蛋白质系统地研究了HIPIPs和铁氧还蛋白之间的氢键效应、溶剂相互作用和改变周围介电场的影响，并将实验结果与密度泛函理论计算相结合。我们还建立了Mo(Tris)二硫烯的成键/几何结构关联以及DMSO还原酶家族中的氧转移机制和模型。在这个方案中，我们计划扩展这一方法，并将其与互补光谱相结合，研究几个铁-S系统，例如SAM与丙酮酸裂解酶激活酶中的Fe4S4簇的相互作用；来自大肠杆菌的MutY-aDNA糖基酶；Fe2S2蛋白与β9去饱和酶的结合；以及Cys-&Gt；Ser突变对铁硫簇中电子离域的影响。我们还打算研究一系列模拟亚硫酸盐氧化酶家族状态的钼单和双氧双(二硫杂环戊烯)络合物。其具体目的是定义酶的电子结构和模型络合物，并了解酶反应的结构和功能之间的相关性。