Regulation of NADH: ubiquinone oxidoreductase (complex *

NADH 的调节：泛醌氧化还原酶（复合物 *

• 批准号: 6645480
• 负责人: Gary Cecchini
• 金额: $ 4.28万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6645480
• 关键词: Commonwealth of Independent States; NAD(P)H oxidoreductase; SDS polyacrylamide gel electrophoresis; active sites; binding sites; complementary DNA; cooperative study; enzyme structure; enzyme substrate; laboratory rat; ligands; mitochondria; mutant; myocardial ischemia /hypoxia; nucleic acid sequence; protein purification; reperfusion; ubiquinone

DESCRIPTION (provided by applicant) NADH:ubiquinone oxidoreductase (complex I) is an energy-transducing membrane-bound protein complex that serves as a major entry point for electrons to the mitochondrial respiratory chain. The multisubunit enzyme complex is encoded by 43 separate genes in mammals. The mammalian enzyme shows extremely complex kinetic behavior, in all forms that retain natural electron transfer pathways. The complex kinetic behavior suggests that two distinct slowly equilibrating forms of the enzyme exist. The active (A) form is catalytically capable to reduce ubiquinone, whereas, the de-active (D) form is not able to transfer electrons to ubiquinone in the membrane. The equilibrium between these two forms is under a refined control by a number of regulatory factors (i.e., pH, divalent cations, temperature, the ubiquinone/ubisemiquinone/ubiquinol ratio). This research will primarily be done in Russia as an extension of NIH grant R01 GM61606. The proposed collaborative work is to extend studies of the regulatory characteristics of the enzyme at the molecular mechanistic level by using a combination of biochemical and molecular approaches. The studies will be done in physiologically relevant systems such as intact hearts and mitochondria, as well as, the kinetic and biochemical approaches in the foreign Co-P.l.'s laboratory. Two major aspects of the ND transition are to be investigated. One is to elucidate the molecular mechanisms of the slow interconversion between the A and D forms involved in the red/ox-dependent D to A transition; and the extremely temperature-dependent A to D transition. Natural ligands and modifiers which affect the rate and equilibrium of the ND transition in vitro will be identified. The second aim focusses on the complex I A/D transition in intact mitochondria in relation to the experimental model of ischemia/reperfusion in Langendorff-pertused rat hearts. The focus of these studies is to determine the possible physiological importance of the A/D transition of complex I as it responds to alterations in cellular metabolism. The catalytic activity of complex I is important for cellular physiology and a number of diseases (diabetes, cardiomyopathy) have been associated with defects in complex I. The research to be undertaken will shed light on the modulation of enzyme activity of this important respiratory complex.

说明书（申请人提供）NADH：泛醌氧化还原酶（复合物I）是一种能量转导膜结合蛋白复合物，作为电子进入线粒体呼吸链的主要入口点。在哺乳动物中，多亚基酶复合物由43个独立的基因编码。哺乳动物的酶表现出极其复杂的动力学行为，在所有形式，保留天然的电子转移途径。复杂的动力学行为表明，存在两种不同的缓慢平衡形式的酶。活性（A）形式能够催化还原泛醌，而失活（D）形式不能将电子转移到膜中的泛醌。这两种形式之间的平衡受到许多调节因素的精细控制（即，pH、二价阳离子、温度、泛醌/泛半醌/泛醇比率）。这项研究将主要在俄罗斯进行，作为NIH资助R 01 GM 61606的扩展。建议的合作工作是通过使用生物化学和分子方法的组合，在分子机制水平上扩展酶的调节特性的研究。这些研究将在生理相关系统中进行，如完整的心脏和线粒体，以及国外Co-P. l.的动力学和生化方法。的实验室。两个主要方面的ND过渡进行了调查。一个是阐明在红/氧化物依赖的D到A转变中所涉及的A和D形式之间的缓慢相互转化的分子机制;以及极端温度依赖的A到D转变。将确定影响体外ND转换速率和平衡的天然配体和改性剂。第二个目标集中在复杂的I A/D转换在完整的线粒体在Langendorff-pertused大鼠心脏缺血/再灌注的实验模型。这些研究的重点是确定复合物I的A/D转换的可能生理重要性，因为它响应于细胞代谢的改变。复合物I的催化活性对于细胞生理学是重要的，并且许多疾病（糖尿病、心肌病）已经与复合物I的缺陷相关。即将进行的研究将阐明这种重要的呼吸复合物的酶活性的调节。