Bacterial cytochrome bc1:structure, function, biogenesis

描述（由申请人提供）：生命系统的一个重要特征是它们能够有效地产生生物能量（ATP）。ATP是细胞功能所必需的，包括生物合成、运输、信号转导、趋化性和趋光性以及产热。产生能量的复合体在生物体中广泛存在，它们的功能不正常会导致毁灭性的健康问题和人类疾病，以及植物的低产量。该项目的长期目标是了解能量途径中细胞色素（cyt）组分的结构、功能机制和生物起源。细菌为这些与真核细胞器相关的研究提供了极好的模型系统。本项目将采用分子遗传学、蛋白质组学、生物化学和生物物理学方法，重点研究膜结合细胞色素bc 1的结构-功能和生物发生之间的关键联系。这是一种至关重要的酶，其缺失或功能障碍是多种人类疾病的原因，包括许多肌肉和神经系统疾病。细胞色素bc 1的三维结构的分辨率揭示了其FeS蛋白亚基的流动性，现在导致其功能机制的化学描述，而我们对其生物起源的理解即使在更简单的细菌中也仍然是基本的。具体目标包括探测FeS蛋白运动的控制机制，以避免不必要的副反应，创造新的bc 1复合物变体，以可视化难以监测的内部反应步骤，并表征能量转导细胞色素C复合物的新生物合成组分，包括掺入其辅基。这些研究将极大地提高我们对cytbc 1作为原型酶的结构、功能机制和生物起源的理解和认识。使用这种更简单的系统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物，并可以为阐明线粒体和其他人类疾病和衰老的分子基础提供指导。

DESCRIPTION (provided by applicant): A vital characteristic of living systems is their ability to produce biological energy (ATP) efficiently. ATP is essential for cellular functions including biosynthesis, transport, signal transduction, chemo- and photo-taxis and thermogenesis. Energy producing complexes are widespread among organisms, and their improper function leads to devastating health problems and human diseases and low crop yields in plants. The long-term goal of this project is to understand the structure, mechanism of function and biogenesis of cytochrome (cyt) components of energy pathways. Bacteria provide excellent model systems for these studies that are pertinent to eukaryotic organelles. This project will use molecular genetics, proteomics, biochemical and biophysical approaches, with a sharp focus on the critical links between the structure-function and the biogenesis of the membrane-bound cyt bc1. This is a crucial enzyme whose absence or malfunction is the cause of multiple human diseases, including many muscular and neurological disorders. Resolution of the 3D structure of the cyt bc1 revealed the mobility of its FeS protein subunit, and is now leading to a chemical description of its mechanism of function, while our understanding of its biogenesis remains rudimentary even in simpler bacteria. The specific aims include probing the control mechanisms of the FeS protein motion to avoid unwanted side reactions, creating novel bc1 complex variants to visualize the internal reaction steps that are difficult to monitor, and characterizing novel biogenesis components of energy transducing cyt c complexes, including incorporation of their prosthetic groups. These studies will greatly enhance our understanding and knowledge of the structure, mechanism of function and biogenesis of the cyt bc1 as a prototype enzyme. Insights gained using this simpler system are generally applicable to the structurally more complex and yet functionally similar organelle-derived complexes, and could provide guiding lights for elucidating the molecular bases of mitochondrial and other human diseases and aging.