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: 6465349
• 负责人: Stephen P. Cramer
• 金额: $ 25.91万
• 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 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6465349
• 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的 了解含金属酶的工作原理有多重要。在这个提案中， 我们专注于同时含有 Fe 和不同金属（Ni、Mo、 V) 在活性位点。三个酶活性位点（NiFe 氢化酶、CO 脱氢酶和乙酰辅酶A合酶）含有Fe和Ni的组合。这 另一种酶，固氮酶，在 MFe7S8 簇的一端使用 V 或 Mo。 尽管 X 射线衍射（或电子显微镜）技术取得了进步，但许多 有关分子和电子结构的问题需要解决。这 催化机制仍然知之甚少。 将使用扩展 X 射线研究 Ni 位点的分子结构 H2ase 和 CODH 晶体的吸收精细结构 (EXAFS) 分析。 仅包含 CO 氧化（C 簇）和 ACS（A 簇）位点的样品 也将受到审查。尽管这些酶已经被研究过 EXAFS、建议的样本和范围扩展分析技术应该产生 有关 Ni 站点的更多详细信息。 Ni 和 V 位点的电子结构将使用 X 射线探测 共振拉曼光谱（XRRS 或 RIXS）。对这些光谱的分析将 揭示了 Ni 和 V 氧化和自旋态的最佳描述 各种条件。 Fe 和 Ni 中心振动态密度 将使用振动穆斯堡尔光谱进行研究。这种做法 将有助于识别重要的 M-H 和金属-基底相互作用的位点。 将建造一个仪器来进行校园实验。 上述酶对于维持我们的环境非常重要。铁蛋白 在人类健康和疾病中也发挥着关键作用。拟议的工作将加强 我们对铁生物化学的了解以及光谱技术 开发将应用于解决广泛的生物无机问题。