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有效地产生生物能量(ATP)的能力。ATP对细胞的生物合成、运输、信号转导、趋化性、趋光性和产热等功能是必不可少的。能量产生复合体在生物体中广泛存在，其不适当的功能会导致毁灭性的健康问题和人类疾病，以及植物的低作物产量。该项目的长期目标是了解能量转导途径中细胞色素(Cyt)成分的结构、功能机制和生物发生。这些都是重要的酶，它们的缺失或故障是多种人类疾病的原因，包括许多肌肉和神经疾病。对于这些研究，原核生物提供了更简单的模型系统，这些系统在进化上是保守的，与真核细胞器密切相关。本项目采用分子遗传学、生物化学和生物物理方法，重点研究细胞色素bc1或复合体III的结构和功能。这项建议的具体目标包括：1-细胞色素bc1的喹酚氧化位点的耐氧性的分子基础，以解决有氧酶如何在有氧的情况下避免产生不需要的活性氧物种；2-探索细胞色素b的锌结合残基，以探索它们参与H+传导；以及3-异二聚体细胞色素bc1的开发和表征，以解决细胞bc1内和单体内和单体间的结构和功能沟通和调节，探讨该酶的二聚体结构与作用机制之间的联系。这些研究有望极大地提高我们对能量转导酶的认识和认识。使用更简单的细菌系统获得的信息通常可以适用于结构更复杂但功能相似和进化相关的细胞器衍生酶，并可以为阐明线粒体和其他人类疾病的分子基础和诊断提供宝贵的信息，包括神经疾病、肌肉疾病和衰老。 公共卫生相关性： 本研究旨在明确能量转导酶的结构与功能及其生物发生机制。这些蛋白质是对人类细胞极其有害的活性氧物种的主要来源，它们的生物发生成分构成了人类许多常见线粒体疾病的分子基础。这些酶的功能障碍会导致多种人类疾病，从母体遗传的线粒体疾病到神经肌肉退行性疾病，以及癌症和衰老。

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 as well as 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 transduction pathways. These are important enzymes whose absence, or malfunction are the causes of multiple human diseases, including many muscular and neurological disorders. For these studies, prokaryotes provide simpler model systems that are evolutionarily conserved and closely related to eukaryotic organelles. This project uses molecular genetics, biochemical and biophysical approaches, with a sharp focus on the structure and function of the cyt bc1 or Complex III. The specific aims of this proposal include 1- the molecular basis of oxygen tolerance of the quinol oxidation site of the cyt bc1 to address how this aerobic enzyme avoids the production of unwanted reactive oxygen species in the presence of oxygen, 2- exploration of the Zn binding residues of cyt b at the Qo site to probe their involvement in H+ conduction, and 3- development and characterization of heterodimer cyt bc1 variants to address intra- and inter-monomer structural and functional communications and regulations within the cyt bc1, to probe the links between the dimeric architecture and the mechanism of function of this enzyme. These studies are expected to greatly enhance our understanding and knowledge of energy transduction enzymes. Information gained using the simpler bacterial system could be generally applicable to the structurally more complex but functionally similar and evolutionarily related organelle-derived enzyme, and could provide invaluable information for elucidating the molecular bases and diagnoses of mitochondrial and other human diseases, including neuropathies, myopathies and aging. PUBLIC HEALTH RELEVANCE: This research aims to define the structure-function and biogenesis of energy transduction enzymes. These proteins are the major sources of reactive oxygen species that are extremely harmful for human cells, and their biogenesis components form the molecular bases of many common mitochondrial diseases in humans. Malfunction of these enzymes induce multiple human illnesses, extending from maternally inherited mitochondrial diseases to neuromuscular degenerative disorders, as well as cancer and aging.