Structure Function & Biosynthesis of Respiratory Enzymes

结构 功能

• 批准号: 8309196
• 负责人: VICTOR L DAVIDSON
• 金额: $ 31.98万
• 依托单位: UNIVERSITY OF CENTRAL FLORIDA
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8309196
• 关键词: Aging; Amino Acids; Anabolism; Binding; Biochemical; Biogenesis; Biological; Biological Products; Calcium Binding; Catalytic Domain; Cells; Cellular Structures; Collaborations; Complex; Copper; Coupled; Crystallography; Development; Disease; Distal; Electron Transport; Electrons; Enzymes; Free Radicals; Goals; Health; Heme; Hydrogen; Hydrogen Bonding; Hydroquinones; Indoles; Kinetics; Ligands; Ligation; Mediating; Metabolism; Metal Binding Site; Mitochondrial Myopathies; Modification; Molecular; Mono-S; Neutron Diffraction; Oxidants; Oxidative Stress; Oxygen; Positioning Attribute; Post-Translational Protein Processing; Process; Production; Protein Biosynthesis; Protein Precursors; Proteins; Reaction; Reactive Oxygen Species; Research Project Grants; Respiration; Role; Site; Site-Directed Mutagenesis; Solvents; Structure; Structure-Activity Relationship; Tryptophan; chemical kinetics; cofactor; covalent bond; crosslink; cytochrome c; insight; meetings; methylamine dehydrogenase; novel; oxidation; oxidative damage; polypeptide; protein complex; protein protein interaction; protein structure function; protonation; respiratory enzyme

DESCRIPTION (provided by applicant): This proposal will describe how specific enzymes control the transfer of reactive electrons and the activation of molecular oxygen, while minimizing oxidative damage. This is central to cell development, health and survival. This research project includes studies of enzyme reaction mechanisms, protein structure-function relationships, protein-protein interactions, protein post- translational modification, and mechanisms of long range biological electron transfer. Kinetic, biochemical, spectroscopic and structural studies together with site-directed mutagenesis will be used in these studies. This proposal focuses on the mechanism of biosynthesis of the protein- derived cofactor, tryptophan tryptophylquinone (TTQ), and the structure and function of a novel di-heme enzyme MauG which catalyzes the oxygenation and cross-linking of specific tryptophan residues during TTQ biogenesis in methylamine dehydrogenase (MADH). The substrate for MauG is a 119-kDa precursor protein of MADH with mono-hydroxylated 2Trp57 and no cross- link. MauG catalyzes the 6-electron oxidation of the substrate that results in the second oxygenation of 2Trp57, cross-linking of 2Trp57 and 2Trp108, and oxidation of the quinol product of the first two reactions to form oxidized TTQ. These studies will describe a new biological mechanism for oxygen activation and factors that make specific amino acid residues in proteins susceptible to oxidative modification. The results will provide insight for development of strategies to introduce novel catalytic sites into proteins and manipulate the functions of enzyme-bound hemes, as well as provide clues as to how one might mitigate naturally occurring oxidative damage to proteins. Ongoing mechanistic studies of biological electron transfer (ET) in the MADH-amicyanin-cytochrome c-551i protein complex will be extended and new ET studies will be initiated with MauG. Defining the mechanisms of long range electron transfer reactions will enhance our understanding of the fundamental processes of respiration and intermediary metabolism at the molecular level. A fundamental understanding of the mechanisms of control of biological ET reactions will provide insight into how defective protein ET leads to production of reactive oxygen species and free radicals both of which are associated with many disease states, oxidative stress and aging. PUBLIC HEALTH RELEVANCE: Project Narrative: Reactive oxygen species and free radicals, which are produced as by-products of biological electron transfer and oxygen metabolism, cause non-specific oxidative damage to cell components that causes mitochondrial myopathies, many disease states, oxidative stress and aging. However, free radicals and reactive oxygen species are also required for, and used productively in biosynthetic processes. This proposal will elucidate how specific enzymes control the transfer of reactive electrons and the activation of molecular oxygen, while minimizing oxidative damage.

描述（由申请人提供）： 该建议将描述特定酶如何控制反应性电子的转移和分子氧的激活，同时最大程度地减少氧化损伤。这对于细胞发育，健康和生存至关重要。该研究项目包括研究酶反应机制，蛋白质结构功能关系，蛋白质 - 蛋白质相互作用，蛋白质后翻译后修饰以及远程生物电子转移的机制。这些研究将使用动力学，生化，光谱和结构研究以及定位的诱变。该提议的重点是蛋白质衍生的辅助因子，色氨酸苯基喹酮（TTQ）的生物合成机制，以及一种新型的二烷基酶Maug的结构和功能，从而催化特定甲基化甲基化酶（甲基化甲基化酶）在TTQ生物发生过程中催化特定的色氨酸残基的氧合和交叉链接。 MAUG的底物是MADH的119 kDa前体蛋白，具有单羟基化的2TRP57，没有交叉链路。 MAUG催化底物的6电子氧化，从而导致第二次氧合2TRP57，2TRP57和2TRP108的交联，并氧化前两种反应的Quinol乘积以形成氧化的TTQ。这些研究将描述一种新的生物学机制以及使蛋白质中特异性氨基酸残基易受氧化修饰的因素。结果将为开发策略的发展提供洞察力，以将新型催化位点引入蛋白质并操纵酶结合的血液的功能，并提供有关如何减轻对蛋白质自然氧化损害的线索。 MADH-杏仁蛋白 - 环形C-551I蛋白质复合物中生物电子转移（ET）的持续机械研究将扩展，并将使用MAUG启动新的ET研究。定义远程电子转移反应的机制将增强我们对分子水平上呼吸和中间代谢的基本过程的理解。对控制生物ET反应机制的基本理解将为有缺陷的蛋白质ET如何导致活性氧和自由基的产生，这两者都与许多疾病状态，氧化应激和衰老有关。公共卫生相关性：项目叙述：活性氧和自由基作为生物电子转移和氧代谢的副产品产生，会对细胞成分引起非特异性氧化损害，从而导致线粒体肌病，许多疾病状态，许多疾病状态，氧化应激和衰老。但是，也需要自由基和活性氧，并在生物合成过程中有效地使用。该建议将阐明特定酶如何控制反应性电子的转移和分子氧的激活，同时最大程度地减少氧化损伤。