Molecular mechanism of redox driven proton pumps

氧化还原驱动质子泵的分子机制

• 批准号: 7895528
• 负责人: MARIAN FABIAN
• 金额: $ 22.88万
• 依托单位: RICE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7895528
• 关键词: ATP Hydrolysis; Address; Aging; Apoptosis; Attention; Bacteriorhodopsins; Binding; Binding Proteins; Biochemical; Bioenergetics; Catalytic Domain; Cattle; Complex; Coupled; Coupling; Cytochrome bc1 Complex; Defect; Degenerative Disorder; Detergents; Dioxygen; Electron Spin Resonance Spectroscopy; Electron Transport; Electrons; Enzymes; Free Energy; Free Radicals; Freezing; Functional disorder; Generations; Goals; Heart; Heme; Heme aa3 Cytochrome Oxidase; Hydrogen; Investigation; Kinetics; Ligand Binding; Light; Link; Malignant Neoplasms; Medical; Membrane; Membrane Transport Proteins; Methods; Mitochondria; Mitochondrial Diseases; Modeling; Molecular; Molecular Machines; Movement; Nature; Nitric Oxide; Optics; Oxidases; Oxidation-Reduction; Oxygen; Phospholipids; Photosynthetic Reaction Centers; Principal Investigator; Process; Proteins; Proton Pump; Protons; Pump; Reaction; Research; Respiration; Rhodobacter sphaeroides; Side; Signaling Molecule; Site; Source; Structure; Submitochondrial Particles; Testing; Thermodynamics; Time; Transducers; Variant; Vesicle; Water; biological systems; chemical reaction; copper oxidase; cytochrome c oxidase; design; flash photolysis; interest; oxidation; prevent; programs; research study; respiratory

Coupled electron and proton transfer is recognized as the universal principle of primary energy conservation in respiration. Terminal respiratory oxidases are membrane-bound electron- transfer complexes that catalyze the reduction of oxygen to water and this reaction is associated with the generation of a transmembrane proton gradient that is the primary source of cellular free energy. Oxidases utilize two basic principles to produce the proton gradient. The first is a classical Mitchell's loop mechanism in which electrons and protons for the water formation are taken up from the opposite sides of membrane. The second one is proton pumping in which proton transfer across the membrane is driven by the free energy provided by a redox reaction. However, the mechanism of proton pumping has not been elucidated in any proton pump driven by reduction-oxidation reactions and it remains one of the key problems of molecular bioenergetics. Proposed investigations will contribute to an understanding of the proton translocation mechanism by identification of the electron-proton coupling sites and experimental examination and establishment of the mechanistic principles of pumping and proton gating in heme-copper oxidases. The application of optical spectroscopy, electron paramagnetic resonance, rapid freeze-quenching, flash photolysis, stopped-flow, and several biochemical methods will be utilized to achieve these goals. Specific aims will be addressed using the purified bovine heart oxidase, enzyme incorporated into phospholipid vesicles and in submitochondrial particles.

电子和质子的耦合转移是公认的一次能源的普遍原理 呼吸作用中的守恒。呼吸末端氧化酶是一种膜结合电子- 催化氧还原为水的转移络合物，该反应与 随着跨膜质子梯度的产生，这是细胞的主要来源 自由能。氧化酶利用两个基本原理来产生质子梯度。第一个是一个 经典的Mitchell环机制，其中用于水形成的电子和质子 从膜的反面被卷起的。第二种是质子泵浦， 质子跨膜转移是由氧化还原反应提供的自由能驱动的。 然而，在任何质子泵中，质子泵的机制还没有被阐明。 在还原-氧化反应的驱动下，它仍然是分子研究的关键问题之一 生物能量学。拟议的调查将有助于理解质子 通过确定电子-质子耦合位置和电子转移机制 抽水蓄能机械原理的实验检验与建立 血红素-铜氧化酶中的质子门控。光学光谱学、电子技术的应用 顺磁共振、快速冷冻猝灭、闪光光解、停流等 将利用生化方法来实现这些目标。具体目标将得到解决 使用纯化的牛心脏氧化酶，酶掺入磷脂小泡和在 亚线粒体颗粒。