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）：拟开展的工作重点是黄嘌呤氧化还原酶和一氧化碳脱氢酶两种含钼酶的基本结构/活性研究。第一种酶催化人体嘌呤代谢的最后两步，也是治疗高尿酸血症和化疗方案的重要治疗靶点。它已成为钼羟基化酶家族酶的机理研究范式。第二种酶在某些细菌的CO上催化羧营养生长的关键步骤，负责每年从环境中去除大约2 × 108公吨的CO。从化学的角度来看，这也是一个基本的生物反应：尽管CO脱氢酶与黄嘌呤氧化还原酶具有显著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键的切割。这项工作的总体目标是更全面地了解这两种酶在其结构背景下的作用机制，指导假设是酶的功能是由活性位点的物理和电子结构决定的。具体目标包括快速动力学研究以及旨在确定鉴定的中间体的电子结构的光谱工作。在黄嘌呤氧化还原酶的情况下，靶向特定活性位点氨基酸残基的位点定向突变体将被检查以评估其在催化中的作用。总的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。