Structural Studies on Membrane-Associate Cytochrome B5 and P450 NMR

描述（由申请人提供）：拟议研究的主要目的是确定16.7 kDa膜相关细胞色素b5的结构，这是一种在多种细胞类型中发现的电子转移蛋白。它在细胞色素- p450的催化活性中起主要作用，细胞色素- p450代谢当今临床使用的50%以上的药物。它还作为电子转移组分参与生物组织中的许多氧化反应，包括脂肪和类固醇的合成代谢。这对蛋白质结构测定的实验技术提出了重大挑战。然而，利用核磁共振光谱法测定膜蛋白的结构还处于快速发展阶段；近年来对几种膜蛋白的研究结果表明，细胞色素b5的结构测定是可行的。细胞色素b5的结构将通过溶液核磁共振和固态核磁共振技术确定在胶束和脂质双层中的结构。在游离和与细胞色素- p450络合中获得的结构将为细胞色素-b5影响细胞色素- p450催化作用的分子机制提供见解。公共卫生相关性：拟议的细胞色素-b5结构研究的结果将提供细胞色素-b5影响细胞色素- P450氧化的分子机制的见解，细胞色素- P450代谢超过50%的当前药物。这些研究还将使我们了解细胞色素b5在维持细胞膜完整性所必需的睾酮和许多不饱和脂质的生物合成中的作用。

DESCRIPTION (provided by applicant): The main objective of the proposed research is to determine the structure of a 16.7 kDa membrane-associated cytochrome-b5, an electron transfer protein found in a variety of cell types. It plays a major role in the catalytic activity of cytochrome-P450, which metabolizes more than 50% of the drugs in clinical use today. It is also involved as an electron transfer component in a number of oxidative reactions in biological tissues, which includes the anabolic metabolism of fats and steroids. It presents significant challenges for experimental techniques of protein structure determination. However, structure determination of membrane proteins by NMR spectroscopy is in a rapid phase of development; recent results on several membrane proteins are promising and indicate that the structure determination of cytochrome-b5 is feasible. The structure of cytochrome-b5 will be determined in micelles by solution NMR and in lipid bilayers by solid state NMR techniques. Structures obtained in free and in complexation with cytochrome-P450 will provide insights into the molecular mechanism by which cytochrome-b5 influences the catalysis of cytochrome-P450. PUBLIC HEALTH RELEVANCE: The outcome of the proposed structural studies on cytochrome-b5 will provide insights into molecular mechanism by which cytochrome-b5 influences oxidation by cytochrome- P450 that metabolizes more than 50% of current-day drugs. These studies will also enable us to understand the role of cytochrome-b5 in the biosynthesis of testosterone and numerous unsaturated lipids, which are necessary for maintaining the integrity of cellular membranes.