Function and assembly of heme-copper oxidases in aerobic respiratory chains

有氧呼吸链中血红素铜氧化酶的功能和组装

• 批准号: 153113-2012
• 负责人: Hill, Bruce
• 金额: $ 2.04万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=522523
• 关键词: Function; assembly; heme; copper; oxidases

All cells engage in a process of energy conversion in which food is broken down and some energy is harvested. This energy is then used to fuel biochemical synthesis, nutrient transport and cellular mobility. There are a set of enzymes that act to catalyze the processes of energy transfer and the study of these enzymes and their mechanisms of action make up a large part of the field of bioenergetics. For organisms that use oxygen for respiration a large fraction of energy conversion derives from the process of the conversion of oxygen to water. This reaction is catalyzed in aerobic species by a member of the heme-copper oxidase family of enzymes. Members of the heme-copper oxidase family are distinguished by an oxygen reaction site that includes a heme moiety and a copper ion that are closely spaced and highly cooperative n their reaction with oxygen. The research in this proposal is aimed at understanding the molecular mechanism used by the heme-copper oxidase family of enzyme to convert oxygen to water, and the harvesting of energy from this process. We use a combination of spectroscopic and kinetic approaches along with recombinant DNA methods to make mutant enzymes to unravel the physical details of these mechanisms to atomic detail. A second aspect of this proposal is to understand how these catalysts, which are essentially molecular machines, are put together. The process of assembly for heme-copper oxidases is intrinsically complex as it involves the assembly of several protein subunits and the simultaneous insertion of four reactive metal centers. The regulation of this process is important for its success. We are interested particularly in the delivery and incorporation of copper ions into the heme-copper oxidase complex. This process involves a specific copper binding protein that acts to chaperone the metal ion into its site of action in the heme-copper enzyme. Our studies will give insight into the functional aspects of energy transfer and how these systems are assembled. A central aspect of our progam is training highly qualified personnel in the application of biophysical approaches to understaniding biochemical mechanisms and to place their findings into the context of a biological system.

所有细胞都参与能量转换过程，其中食物被分解并收获一些能量。然后，这种能量被用来为生化合成、营养运输和细胞流动性提供燃料。有一系列的酶催化能量转移的过程，这些酶及其作用机制的研究构成了生物能量学领域的很大一部分。对于使用氧气进行呼吸的生物体，大部分能量转换来自氧气转化为水的过程。该反应在需氧物种中由血红素-铜氧化酶家族的酶催化。血红素-铜氧化酶家族的成员的特征在于氧反应位点，所述氧反应位点包括血红素部分和铜离子，所述血红素部分和铜离子紧密间隔并且在它们与氧的反应中高度协同。 这项研究的目的是了解血红素铜氧化酶家族将氧气转化为水的分子机制，以及从这一过程中收获能量。我们使用光谱和动力学方法的组合，沿着重组DNA的方法，使突变酶解开这些机制的原子细节的物理细节。这个提议的第二个方面是了解这些催化剂，它们本质上是分子机器，是如何放在一起的。血红素-铜氧化酶的组装过程本质上是复杂的，因为它涉及几个蛋白质亚基的组装和四个活性金属中心的同时插入。对这一进程的监管对其成功至关重要。我们特别感兴趣的是在铜离子的交付和纳入血红素铜氧化酶复合物。这一过程涉及一种特异性的铜结合蛋白，该蛋白的作用是陪伴金属离子进入血红素铜酶的作用位点。我们的研究将深入了解能量转移的功能方面以及这些系统是如何组装的。我们的研究的一个中心方面是培养高素质的人员在生物物理方法的应用，以了解生化机制，并把他们的发现到生物系统的背景下。