Molecular mechanism of redox driven proton pumps

氧化还原驱动质子泵的分子机制

基本信息

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
项目类别：
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

项目摘要

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.

电子和质子耦合转移被认为是一次能源的普遍原理呼吸守恒。末端呼吸氧化酶是膜结合电子催化氧还原成水的转移络合物，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源。氧化酶利用两个基本原理来产生质子梯度。第一个是经典的米切尔循环机制，其中形成水的电子和质子是从膜的相对两侧取出。第二种是质子泵浦，其中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，质子泵的质子泵浦机制尚未阐明。由氧化还原反应驱动，它仍然是分子生物学的关键问题之一生物能量学。拟议的研究将有助于了解质子通过识别电子-质子耦合位点的易位机制和泵送和机械原理的实验检查和建立血红素铜氧化酶中的质子门控。光谱学、电子学的应用顺磁共振、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。将解决具体目标使用纯化的牛心氧化酶，将酶掺入磷脂囊泡中并在软骨下颗粒。