Structure/activity studies of two molybdenum enzymes

两种钼酶的结构/活性研究

• 批准号: 7094249
• 负责人: Russ Hille
• 金额: $ 24.09万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-12 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7094249
• 关键词: active sites; carbon monoxide; catalyst; enzyme activity; enzyme mechanism; enzyme structure; molybdenum; oxygenases; protein structure function; site directed mutagenesis; spectrometry; xanthine oxidase

DESCRIPTION (provided by applicant): The proposed work focuses on basic structure/activity studies of two molybdenum-containing enzymes, xanthine oxidoreductase and carbon monoxide dehydrogenase. The first enzyme catalyzes the final two steps in purine metabolism in humans, and is also an important therapeutic target in the treatment of hyperuricemia and also in chemotherapeutic regimens. It has become the paradigm for mechanistic studies of the molybdenum hydroxylase family of enzymes. The second enzyme catalyzes the key step in carboxydotrophic growth on CO in certain bacteria and is responsible for removal of approximately 2 x 108 metric tons of CO from the environment each year. It is also a biological reaction of fundamental interest from a chemical standpoint: although CO dehydrogenase exhibits significant structural and sequence homologies to xanthine oxidoreductase, it is unique among the molybdenum hydroxylases in that its reaction does not involve C-H bond cleavage. The overall goal of the proposed work is to gain a more complete understanding of the mechanism of action of these two enzymes in the context of their structures, the guiding hypothesis being that enzyme function is dictated by the physical and electronic structure of the active site. The Specific Aims include rapid kinetic studies as well as spectroscopic work aimed at determining the electronic structures of intermediates identified. In the case of xanthine oxidoreductase, site-directed mutants targetting specific active site amino acid residues will be examined to evaluate their roles in catalysis. The overall goal is to compare and contrast the behavior of these two closely related enzymes so that the relationship of structure to function can be better understood.

描述（由申请人提供）：拟议的工作重点是两种含钼酶，黄嘌呤氧化还原酶和一氧化碳脱氢酶的基本结构/活性研究。第一种酶催化人体嘌呤代谢的最后两个步骤，也是高尿酸血症治疗和化疗方案的重要治疗靶点。它已成为钼羟化酶家族机理研究的范例。第二种酶催化某些细菌中二氧化碳一氧化碳营养生长的关键步骤，每年从环境中去除约 2 x 108 公吨二氧化碳。从化学角度来看，这也是一种具有根本意义的生物反应：虽然CO脱氢酶与黄嘌呤氧化还原酶表现出显着的结构和序列同源性，但它在钼羟化酶中是独特的，因为它的反应不涉及C-H键裂解。拟议工作的总体目标是更全面地了解这两种酶在其结构的背景下的作用机制，指导假设是酶的功能由活性位点的物理和电子结构决定。具体目标包括快速动力学研究以及旨在确定已识别中间体的电子结构的光谱工作。就黄嘌呤氧化还原酶而言，将检查针对特定活性位点氨基酸残基的定点突变体，以评估其在催化中的作用。总体目标是比较和对比这两种密切相关的酶的行为，以便更好地理解结构与功能的关系。