MOLECULAR GENETICS OF THE CYTOCHROME BC1 COMPLEX

细胞色素 BC1 复合物的分子遗传学

• 批准号: 6498660
• 负责人: M. FEVZI DALDAL
• 金额: $ 28.14万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-12-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6498660
• 关键词: NADPH cytochrome c2 reductase; Rhodospirillales; bacterial genetics; bacterial proteins; chemical kinetics; cytochrome b; cytochrome c; electron spin resonance spectroscopy; iron sulfur protein; microorganism culture; molecular genetics; protein folding; protein structure function; ubiquinone

A vital characteristic of living systems is their ability to perform efficient energy conversion. Biological energy transduction is the ensemble of pathways necessary for cellular energy (ATP) production, which is essential for many cellular functions, including macromolecular biosynthesis, solute transport, signal transduction, chemotaxis, phototaxis and thermogenesis. The long term goal of this project is to define the cytochrome (cyt) components of these pathways, and to understand their structure, mechanism of function and biogenesis (i.e., assembly, maturation and regulation). Facultative phototrophic bacteria (e.g., Rhodobacter species) provide an excellent model system for eukaryotic organelles. The energy transduction complexes are widespread among living organisms, and their improper function leads to devastating neuromuscular and mitochondrial diseases in humans, and low crop yields in plants. This project will continue molecular and biochemical genetics of these complexes, focusing on the structure, function and biogenesis of membrane-bound, multisubunit cyt c complexes (i.e., the ubihydroquinone: cyt c oxidoreductase, or the bc1 complex, and the cbb3-type cyt c oxidase). Major progress has recently been accomplished by the resolution of the 3D structure of the bc1 complex, and recognition of the mobility of its FeS protein subunit. in the light of these excitements, the specific aims include the analysis of the FeS protein motion and its control during Q0 site catalysis; direct and rapid activation of the bc1 complex using photoactivatable compounds to study the movement of the FeS protein as a unique intra-protein electron shuttle device; construction of novel cyt c1 molecules with unusual ligand and folding properties; engineering of novel bc1 complex variants to correlate their structural flexibility and functional similarities; and genetic and biochemical studies of mutants and gene products involved in the biogenesis of multisubunit cyt c complexes and incorporation of their prosthetic group. These studies will increase significantly our understanding of the structure and mechanism of function of the bc1 complex as a prototype for a unique intra-protein electron shuttle device, and pave the road to future "single molecule" studies. They will also provide important insights into the biogenesis of membrane-bound multisubunit cyt c complexes that operate during cellular energy production, an important biological process that is far from being completely understood, even in bacteria. Finally, insights gained in this simpler system are generally applicable to the structurally more complex and yet functionally similar organelle-derived complexes, and are important for the elucidation of the molecular basis of mitochondrial diseases and aging.

生命系统的一个重要特征是它们有能力进行有效的能量转换。生物能量转导是细胞产生能量(ATP)所必需的一系列途径，在许多细胞功能中是必不可少的，包括大分子生物合成、溶质运输、信号转导、趋化、趋光和产热。该项目的长期目标是确定这些途径的细胞色素(Cyt)成分，并了解它们的结构、功能机制和生物发生(即组装、成熟和调节)。兼性光养细菌(如红细菌)为真核细胞器提供了一个很好的模型系统。能量转导复合体广泛存在于生物体内，其不合理的功能导致人类患上毁灭性的神经肌肉和线粒体疾病，并导致植物减产。该项目将继续这些复合体的分子和生化遗传学，重点研究膜结合的多亚单位Cytc复合体(即泛氢苯二酚：Cytc氧化还原酶或Bc1复合体，以及CBB3型Cytc氧化酶)的结构、功能和生物发生。最近在解析Bc1复合体的3D结构和识别其FES蛋白亚基的迁移率方面取得了重大进展。鉴于这些刺激，具体目标包括分析Q0位催化过程中FeS蛋白的运动及其控制；利用可光激活化合物直接快速激活Bc1复合体，以研究FeS蛋白作为独特的蛋白质内电子穿梭装置的运动；构建具有特殊配体和折叠特性的新型cytc1分子；设计新的Bc1复合体变异体，使其结构灵活性和功能相似性相互关联；以及参与多亚单位cytc复合体的生物发生和其辅基掺入的突变体和基因产品的遗传和生化研究。这些研究将大大加深我们对Bc1复合体作为独特蛋白质内电子穿梭装置原型的结构和功能机制的理解，并为未来的单分子研究铺平道路。它们还将为膜结合的多亚单位细胞色素c复合体的生物发生提供重要的见解，这些复合体在细胞能量产生过程中工作，这是一个重要的生物过程，即使在细菌中也远未完全了解。最后，在这个更简单的系统中获得的见解通常适用于结构更复杂但功能相似的细胞器衍生复合体，并对阐明线粒体疾病和衰老的分子基础很重要。