MOLECULAR GENETICS OF THE CYTOCHROME BC1 C COMPLEX

泛喹酚：细胞色素c氧化还原酶(bc1复合体)是一种必需的 是细胞能量转导的组成部分，并参与细胞的形成 指产生三磷酸腺苷所必需的膜电位和质子梯度。 这个项目的长期目标是详细地了解分子 术语，细胞色素Bc1复合体如何在电子转移和 矢量质子转移。这种广泛存在的复杂情况对 活细胞，其不正常的功能导致严重的神经和 肌肉疾病。我们的实验系统源自原核生物 荚膜红杆菌是线粒体和蛋白质的模式生物 叶绿体能量转导。在此之前， 用分子遗传学技术建立了细胞色素Bc1复合体。这个 其活性区域之一，对苯二酚氧化(QO)部位的位置是 现在出现了对抑制剂抗性(InhR)突变体的分析。这 该项目将继续对细胞色素T进行分子遗传学和生化分析。 与其功能部位相关的Bc1络合物[苯二酚氧化(qz，o，p)] 和对苯二酚还原(qc，i，n)]结构的不同区域 亚基(FeS蛋白、细胞色素b、细胞色素c1)。为此，(1) 位于QO附近的Cyt b的特定氨基酸残基 结构域将通过饱和突变进行分析；(2)亚单位内和 QO结构域的亚基间相互作用将由第二个站点进行分析 非功能细胞色素b突变体的抑制子；(3) FES蛋白到QO位点的普遍保守残基将是 突变鉴定；(4)细菌Bc1的QI结构域的定位 通过对红螺菌InhR突变体的分析确定复合体 天然敏感种红色及其突变体的构建 以及(5)该基因的结构和功能含义。 Cyt bh和bl hemes的轴向配体之间的残基加成 将会受到考验。这些突变体的特征是遗传的， 生理生化分析。在这个细菌中获得的洞察力 系统一般适用于结构较复杂而又 功能相似的线粒体和叶绿体氧化还原酶， 与了解线粒体的分子基础有关 疾病。这项工作也有助于更好地认识 膜蛋白亚基与其假体的相互作用 在它们的生物发生和组装过程中。

The ubiquinol:cytochrome c oxidoreductase (bc1 complex) is an essential component of cellular energy transduction, and is involved in the formation of a membrane potential and a proton gradient necessary to produce ATP. The long term goal of this project is to understand, in detailed molecular terms, how the cyt bc1 complex functions during electron transfer and vectorial proton translocation. This widespread complex is essential for living cells, and its improper function leads to severe neurological and muscular diseases. Our experimental system derives from the procaryote Rhodobacter capsulatus which is a model organism for mitochondrial and chloroplast energy transduction. Previously, the primary structure of the cyt bc1 complex was established using molecular genetic techniques. The location of one of its active domains, the quinol oxidation (Qo) site, is now emerging from the analysis of inhibitor resistant (InhR) mutants. This project will continue molecular genetic and biochemical analyses of the cyt bc1 complex to correlate its functional sites [quinol oxidation (Qz,o,p) and quinone reduction (Qc,i,n)] with different regions of its structural subunits (FeS protein, cyt b, cyt c1). For this purpose, (1) Role of the specific amino acid residues of cyt b located in the vicinity of the Qo domain will be analyzed by saturation mutagenesis; (2) Intrasubunit and intersubunit interactions at the Qo domain will be analyzed by second site suppressors of non functional cyt b mutants; (3) Contribution of the universally conserved residues of the FeS protein to the Qo site will be assessed by mutagenesis; (4) Location of the Qi domain of a bacterial bc1 complex will be defined by analysis of InhR mutants of Rhodospirillum rubrum, a naturally sensitive species and by construction of Qi mutants of R. capsulatus; and (5) Structural and functional implications of the addition of a residue between the axial ligands of the cyt bH and bL hemes will be tested. These mutants will be characterized by genetic, physiological and biochemical analyses. Insights gained in this bacterial system are generally applicable to the structurally more complex and yet functionally similar mitochondrial and chloroplast oxidoreductases, and are relevant to the understanding of the molecular basis of mitochondrial diseases. This work also contributes to a better recognition of the interactions between the subunits of membrane proteins and their prosthetic groups during their biogenesis and assembly.