X-Ray Raman and Vibrational Mossbauer of Metalloproteins

金属蛋白的 X 射线拉曼和振动穆斯堡尔

• 批准号: 6874836
• 负责人: Stephen P. Cramer
• 金额: $ 20.05万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2007-09-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6874836
• 关键词: Mossbauer spectrometry; Raman spectrometry; X ray spectrometry; active sites; acyl coA dehydrogenases; chemical structure; enzyme mechanism; hydrogenase; iron; metalloenzyme; molybdenum; nickel; oxidation; vanadium

DESCRIPTION (provided by applicant): Our long-term goal is a better understanding of how important metal containing enzymes work. In this proposal, we focus on metalloenzymes that contain both Fe and a different metal (Ni, Mo, V) at the active site. Three of the enzyme active sites (NiFe hydrogenase, CO dehydrogenase, and acetyl-CoA synthase) contain combinations of Fe and Ni. The other enzyme, nitrogenase, employs V or Mo at one end of a MFe7S8 cluster. Despite progress by x-ray diffraction (or electron microscopy) techniques, many questions about the molecular and electronic structure need to be resolved. The catalytic mechanisms are still poorly understood. The molecular structure of the Ni sites will be studied using extended x-ray absorption fine structure (EXAFS) analysis of crystals of H2ase and CODH. Samples containing only the CO oxidation (C-cluster) and ACS (A-cluster) sites will also be examined. Although these enzymes have already been studied by EXAFS, the proposed samples and range-extended analysis techniques should yield more details about the Ni sites. The electronic structure of the Ni and V sites will be probed using x-ray resonance Raman spectroscopy (XRRS or RIXS). Analysis of these spectra will reveal the best description of the Ni and V oxidation and spin states under a variety of conditions. The Fe- and Ni-centered vibrational density of states will be studied using the vibrational Mossbauer spectroscopy. This approach will help identify the sites of important M-H and metal-substrate interactions. An instrument will be built to allow on-campus experiments. The above enzymes are important for maintaining our environment. Fe proteins also play key roles in human health and disease. The proposed work will enhance our knowledge of Fe biochemistry, and the spectroscopic techniques under development will have applications to a wide range of bioinorganic problems.

描述（由申请人提供）：我们的长期目标是更好 了解含有酶的金属的重要性。在此提案中， 我们专注于含有Fe和不同金属的金属酶（Ni，Mo， v）在活动地点。三个酶活性位点（Nife氢化酶，CO 脱氢酶和乙酰-COA合酶）含有Fe和Ni的组合。这 其他酶，氮酶在MFE7S8簇的一端采用V或MO。 尽管X射线衍射（或电子显微镜）技术取得了进展，但许多 需要解决有关分子和电子结构的问题。这 催化机制仍然很了解。 将使用扩展的X射线研究NI位点的分子结构 H2ase和Codh晶体的吸收细胞结构（EXAFS）分析。 仅包含CO氧化（C群集）和AC（A群集）位点的样品 也将被检查。尽管这些酶已经由 EXAFS，提议的样品和范围扩展的分析技术应产生 有关NI网站的更多详细信息。 Ni和V位点的电子结构将使用X射线进行探测 共振拉曼光谱（XRR或RIX）。这些光谱的分析将 揭示Ni和V氧化的最佳描述，并在A下旋转状态 各种条件。状态的Fe和以Fe为中心的振动密度 将使用振动摩斯鲍尔光谱学研究。这种方法 将有助于确定重要的M-H和金属底物相互作用的位置。 将建造仪器以允许校园实验。 上述酶对于维持我们的环境很重要。 Fe蛋白 还在人类健康和疾病中发挥关键作用。拟议的工作将增强 我们对FE生物化学的了解以及下面的光谱技术 开发将在广泛的生物有机问题上应用。