MOLECULAR & CONTROL MECHANISM OF ENERGY COUPLING SITE I

分子

• 批准号: 2291626
• 负责人: Tomoko None Ohnishi
• 金额: $ 2.31万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2291626
• 关键词: NAD(P)H oxidoreductase; bioenergetics; cellular respiration; charge transfer complex; electron spin resonance spectroscopy; electron transport; enzyme structure; free radicals; hydrogen channel; hydropathy; semiquinone; thermodynamics

We propose to study the mechanism of electron and proton transfer pathways in mitochondrial NADH-quinone oxidoreductase (often referred to as Complex I). this complex plays a central role in the oxidation of NADH, the reducing product of cellular metabolism, by the respiratory chain. Complex I is the most complicated and least understood energy transducing proton-motive enzyme of the respiratory chain. the proposed research takes new directions in the investigation of the mechanism, kinetics, and regulatory properties of this complex in both the isolated and membrane-bound states. The specific studies will include: [I] determination of the minimal structure of Complex I capable of catalyzing NADH oxidation which is coupled with vectorial transfer of protons across the membrane; [II] determination of the internal electron transfer sequence within intrinsic redox components of NADH-quinone oxidoreductase by utilizing artificial electron acceptors (transition metal complexes) with proper redox potentials and appropriate other parameters (hydrophilicity, charge, size); [III] physico-chemical studies on the ubisemiquinones associated with the specific binding sites in Complex I which was recently discovered in Russian Co-P.I.'s laboratory; [IV] studies of molecular events involved in the slow active/inactive transition of Complex I, rediscovered recently by the Russian Co-P.I., which will be extended to searches of physiologically relevant factors which are involved in the control of hysteretic behavior of this complex. The P.I. has extensive experience with EPR studies and with thermodynamic analysis of the intrinsic paramagnetic redox centers of mitochondrial and microbial systems. Specifically, the P.I. has made significant contribution in the characterization of iron-sulfur clusters, flavin and ubiquinone free radicals. The Russian Co-P.I. is an established biochemist and has recently developed unique submitochondrial particle preparations having tightly coupled Site I energy transduction. The collaborative program between these investigators, therefore, is expected to greatly enhance the understanding of the mechanism of energy coupling and its regulation.

我们建议研究电子和质子转移的机理 线粒体NADH- Quinone氧化还原酶的途径（通常称为 作为复杂的i）。 这种复合物在氧化中起着核心作用 纳德（NADH）是细胞代谢的减少产物，呼吸道 链。 复杂的我是最复杂，最不理能的能量 呼吸链的转导质子 - 动力酶。 提议 研究采取了新的方向，以调查机制， 该复合物的动力学和调节特性 和膜结合状态。 具体研究将包括：[i] 确定能够催化的复合物I的最小结构 NADH氧化与质子的矢量转移相结合 膜； [ii]确定内部电子转移 NADH-夸酮氧化还原酶的固有氧化还原成分内的序列 通过使用人造电子受体（过渡金属复合物） 具有适当的氧化还原电位和适当的其他参数 （亲水性，电荷，大小）； [iii]关于 与复合物I中的特定结合位点相关的泛素酮 该公司最近在俄罗斯副委员会的实验室中发现了这一点； [iv] 研究参与缓慢活性/非活性的分子事件的研究 复杂I的过渡，最近由俄罗斯共同的Co-i。 将扩展到搜索生理相关因素 这与控制该复合物的滞后行为有关。 P.I.在EPR研究和热力学方面具有丰富的经验 分析线粒体和 微生物系统。 特别是P.I.意义重大 铁硫簇，黄素和 泛酮自由基。 俄罗斯共同。是一个已建立的 生物化学家，最近开发 具有紧密耦合位点I能量转导的制剂。 这 因此，这些调查人员之间的协作计划是期望的 大大增强对能量耦合机理的理解 及其监管。