SINGLE CRYSTAL XAS STUDIES OF HEME CATALYSIS

血红素催化的单晶 XAS 研究

• 批准号: 8169949
• 负责人: BRITT HEDMAN
• 金额: $ 0.34万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8169949
• 关键词: Binding; Camphor; Catalysis; Chemicals; Computer Retrieval of Information on Scientific Projects Database; Crystallography; Cytochrome P450; Cytochrome c Peroxidase; Electronics; Electrons; Enzymes; Funding; Grant; Heme; Hydrogen Peroxide; Hydroxylation; Institution; Ligands; Molecular Conformation; Nature; Oxidation-Reduction; Oxygen; Pseudomonas putida; Research; Research Personnel; Resources; Rest; Saccharomyces cerevisiae; Source; Spectrum Analysis; Structure; System; United States National Institutes of Health; molecular vector; oxidation; programs; vector

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We plan to utilize single crystal XAS to study two representative heme-containing enzymes?cytochrome P450 from Pseudomonas putida, which catalyzes the regio- and stereo-specific hydroxylation of camphor, and cytochrome c peroxidase from Saccharomyces cerevisiae, which catalyzes the two-electron oxidation of hydrogen peroxide. Like most Fe-heme enzymes, these are thought to go through several Fe-oxo intermediates, including an oxy-ferryl state (compound I), as part of their catalytic cycle. Although, these enzymes have been extensively characterized by both crystallography and spectroscopy, questions still remain about the nature of their reactive intermediates. By examining stable, metastable, and radiolytically reduced states of these enzymes using Fe K-edge single crystal XAS, we plan to characterize the structure of their catalytic intermediates through EXAFS analysis concomitant with electronic state determination through analysis of the edge region. Single crystal XAS can be used in anisotropic systems to selectively enhance specific molecular vectors through crystallographic alignment with the beam polarization vector, thereby providing enhanced geometric and electronic details about a molecule. In the cytochrome P450 study, polarized XAS will be used to probe the axial Fe-substrate oxygen and Fe-proximal ligand interactions separately from the Fe-heme interactions. The program outlined herein should provide for a detailed understanding of heme enzyme catalysis through 1) the polarized single crystal XAS study of wild-type and effector bound conformations of cytochrome P450 in the resting state and, potentially, in six other forms produced by camphor incubation, chemical oxidation/reduction, oxygenation, and radiolytic reduction; and 2) the single crystal XAS study of cytochrome c peroxidase in the ferric resting-state, ferryl compound I state, and in the radiolytically generated products of the compound I state.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 We plan to utilize single crystal XAS to study two representative heme-containing enzymes?cytochrome P450 from Pseudomonas putida, which catalyzes the regio- and stereo-specific hydroxylation of camphor, and cytochrome c peroxidase from Saccharomyces cerevisiae, which catalyzes the two-electron oxidation of hydrogen peroxide.像大多数Fe-eme酶一样，这些酶被认为经过了几种Fe-oxo中间体，包括氧曲率（化合物I），作为其催化循环的一部分。尽管这些酶以晶体学和光谱学既具有广泛的特征，却仍然存在有关其反应性中间体的性质的问题。通过使用Fe K-Edge单晶XAS检查这些酶的稳定，亚稳态和放射性降低的状态，我们计划通过EXAFS分析通过EXAFS分析来表征其催化中间体的结构，这些分析与电子状态确定通过分析边缘区域。单晶XAS可用于各向异性系统中，通过与梁极化载体的晶体对齐来选择性增强特定的分子量，从而提供了有关分子的增强的几何和电子详细信息。在细胞色素P450的研究中，极化XA将用于探测与Fe-teme相互作用分别分别与Fe-Ememe相互作用分开的轴向Fe-bubstrate氧和Fe-proximal配体相互作用。本文概述的程序应通过1）通过1）对血红素酶催化的详细理解，对野生型和效应子界面的极化单晶XAS研究在静止状态下的细胞色素p450的结合构象，并有可能以六种形式，由comphor孵化，化学氧化/还原，氧化/还原，氧化，氧化，氧化，氧化，氧化和降低，重新培养，氧化/还原，氧化能力。 2）在铁静止状态，渡轮化合物I状态以及化合物I状态的放射性生成的产物中，细胞色素C过氧化物酶的单晶XAS研究。