BIOINORGANIC CHEMISTRY--CARBON MONOXIDE DEHYDROGENASE

生物无机化学--一氧化碳脱氢酶

• 批准号: 6179369
• 负责人: PAUL A. LINDAHL
• 金额: $ 16.23万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6179369
• 关键词: Clostridium; Mossbauer spectrometry; acetyl coA; active sites; bacterial proteins; carbon monoxide; circular dichroism; electron nuclear double resonance spectroscopy; electron spin resonance spectroscopy; enzyme complex; fluorescence spectrometry; iron; mass spectrometry; metal complex; nickel; nuclear magnetic resonance spectroscopy; oxidoreductase; protein structure function; sulfur

DESCRIPTION: This proposal aims to elucidate the catalytic mechanism of carbon monoxide dehydrogenase from Clostridium thermoaceticum. The structure of the enzyme's nickel and iron-sulfur clusters, their redox and spectroscopic properties, their roles in catalysis, and their relationship to the structure of the protein are of particular interest. Only four nickel containing enzymes are known, and the biochemical properties of Ni are not well understood. Ni complexes are widely used as industrial catalysts, and they serve to cleave DNA site specifically. More detailed knowledge of the catalytic properties of Ni may facilitate development of improved artificial enzymes with biomedical and biotechnological applications. The enzyme catalyses two types of reactions, the reversible oxidation of CO to CO2 and the synthesis of acetyl-coenzyme A. The enzyme has an a2b2 quaternary structure with 2Ni, 11-13 Fe, and approximately 14 S2- ions per ab. The metal ions are organized into three types of clusters, called A,B, and C. The C-and A-clusters are novel Ni-Fe-S clusters that serve as the active sites, while the B-cluster is an Fe4S4 cluster that serves to transfer electrons to external electron-accepting agents. The predominant approach to be taken involves and has involved separating the subunits of the enzyme in a manner that does not destroy the metal clusters. By studying individual subunits and other dissociation products, the desired properties of individual clusters will be elucidated. A variety of physical methods will be used, including Electron Paramagnetic Resonance, Mossbauer, Electron Nuclear Double Resonance, X-ray Absorption, Electronic Absorption, Circular Dichroism, Fluorescence, Mass Spectrometry, and possibly Nuclear magnetic Resonance. Other methods, including kinetics, potentiometric titrations, activity assays, radioactivity and isotope labeling, analytical ultracentrifugation, equilibrium dialysis, and peptide sequencing will also be employed.

描述：该建议旨在阐明催化机制 来自梭状芽胞杆菌的一氧化碳脱氢酶的含量。 这 酶的镍和铁硫簇的结构，它们的氧化还原 和光谱特性，它们在催化中的作用及其 与蛋白质结构的关系特别有趣。 仅知道四个含镍的镍，并且生化 NI的特性尚不清楚。 NI复合物被广泛使用 作为工业催化剂，它们专门裂解DNA位点。 对NI的催化特性的更详细的了解可能有助于 用生物医学和 生物技术应用。 酶催化两种反应，可逆的氧化 CO至CO2和乙酰辅酶A的合成。该酶具有 A2B2 Quaternary结构，具有2NI，11-13 Fe，大约14 s2-- 离子 / ab。 金属离子分为三种类型的簇， 称为A，B和C。C和A群集是新颖的Ni-Fe-S簇 充当活动站点，而B群集是Fe4S4群集 用于将电子转移到外部电子感受剂中。 这 要采取的主要方法涉及并涉及分离 酶的亚基的方式不会破坏金属 集群。 通过研究单个亚基和其他解离 产品，单个集群的所需特性将是 阐明。 将使用各种物理方法，包括 电子顺磁共振共鸣，莫斯鲍尔，电子核双 共振，X射线吸收，电子吸收，圆形二色性， 荧光，质谱法，可能是核磁性 谐振。 其他方法，包括动力学，电位计量计 滴定，活动测定，放射性和同位素标记， 分析性超速离心，平衡透析和肽 测序也将被使用。