MECHANISM OF RESPIRATION AND ENERGY TRANSDUCTION

细胞色素bc1复合物是一种寡聚膜酶， 在真核生物中参与与呼吸有关的能量转导 细胞，并同样参与呼吸，光合电子 转移、反硝化、固氮和硫代谢 细菌了解细胞色素bc1 复杂的能量转换对于理解 细胞能量学 这项研究的目的是了解如何亚单位的 细胞色素bc1复合物参与能量传递活动 的复合物，并阐明这种寡聚体 酶被组装到线粒体内膜中。 该实验基于细胞色素bc1 复合物通过质子动力Q循环机制运作，并且 这种酶的线粒体形式含有多个额外的 在该机制中没有明显功能的亚基。 的 实验旨在回答三个问题。 1. bc1复合物的铁硫蛋白亚基如何催化 Q循环中所需的泛醇的发散氧化 机制？ 2.这些额外的亚单位的功能是什么？ 线粒体bc1复合体 3. 10或11个事件的路径或顺序是什么 这种酶复合物的亚基被组装成内部的 线粒体膜？ 我们正在使用遗传学和生物化学的方法来阐明答案 这些问题的答案。 这些方法包括 分离和操作bc1各亚基的基因 复杂的，表征电子转移反应内的 复合物后，选定的修饰亚基，鉴定 组装复合物的中间步骤，以及纯化和 部分组装的亚复合物的表征和可能的因素 参与了复杂的装配。

The cytochrome bc1 complex is an oligomeric membrane enzyme which participates in energy transduction linked to respiration in eukaryotic cells, and similarly participates in respiration, photosynthetic electron transfer, denitrification, nitrogen fixation, and sulfur metabolism in bacteria. Understanding the molecular basis of how the cytochrome bc1 complex performs this energy transduction is essential to understanding cellular energetics. The objectives of this research are to understand how the subunits of the cytochrome bc1 complex participate in the energy transduction activities of the complex, and to elucidate the pathway by which this oligomeric enzyme is assembled into the inner mitochondrial membrane. The experimentation is based on the rationale that the cytochrome bc1 complex operates by a protonmotive Q cycle mechanism, and that the mitochondrial forms of this enzyme contain multiple supernumerary subunits which have no obvious function in that mechanism. The experimentation is intended to answer three questions. 1. How does the iron-sulfur protein subunit of the bc1 complex catalyze the divergent oxidation of ubiquinol which is required in the Q cycle mechanism? 2. What are the functions of the supernumerary subunits in the mitochondrial bc1 complexes? 3. What is the pathway or sequence of events by which the 10 or 11 subunits of this enzyme complex are assembled into the inner mitochondrial membrane? We are using genetics and biochemical approaches to elucidate the answers to these questions in Saccharomyces cerevisiae. The approaches include isolation and manipulation of genes for individual subunits of the bc1 complex, characterization of electron transfer reactions within the complex following selected modifications to subunits, identification of intermediate steps in the assembly of the complex, and purification and characterization of partially assembled subcomplexes and possible factors involved in assembly of the complex.