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（一种在多种细胞类型中发现的电子转移蛋白）的结构。它在细胞色素P450的催化活性中起主要作用，细胞色素P450代谢了当今临床使用的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，结构测定膜蛋白的NMR光谱是在一个快速的发展阶段，最近的结果对几个膜蛋白是有前途的，并表明细胞色素-b5的结构测定是可行的。细胞色素-b5的结构将在胶束中通过溶液NMR和在脂质双层中通过固态NMR技术来确定。在游离和与细胞色素P450复合中获得的结构将提供细胞色素B5影响细胞色素P450催化的分子机制的见解。公共卫生相关性：对细胞色素-b5的拟议结构研究的结果将提供对细胞色素-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%的当今药物。这些研究还将使我们能够了解细胞色素b5在睾酮和许多不饱和脂质的生物合成中的作用，这是维持细胞膜完整性所必需的。

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.