RUI: Structure and Function of Subunit II of Cytochrome c Oxidase

细胞色素c氧化酶的卡梅隆亚基II是所有真核生物和某些原核生物中呼吸所需的高度保守的蛋白质。 酶复合物是负责将电子从细胞色素c转移到氧的电子传递链的末端成员。 亚基II与细胞色素c结合并通过CuA氧化还原中心接受电子。该蛋白具有几个高度保守的特征，包括两个疏水区，一个保守的芳香区，一些被认为与细胞色素c上的赖氨酸相互作用的带负电荷的氨基酸和一个铜结合位点，如在蓝铜蛋白中发现的那些。 为了了解这种蛋白质的功能，已经产生了亚基II缺陷的酵母突变体。 我们已经确定了菌株的功能缺陷，由于在CuA结合区的改变，并由于在芳香区的密码子取代。 我们正在完成对突变体的分析，并将我们的调查扩展到这些菌株的恢复功能的回复突变体。 我们希望找到恢复野生型序列的真回复突变体;一个氨基酸取代另一个氨基酸的假回复突变体和携带基因外抑制子的菌株。 在后一组中，我们希望确定基因产物，核和线粒体，直接与亚基II相互作用。 这种分析将产生有关蛋白质中功能关键氨基酸的信息，并可能产生有关氧化酶亚基之间相互作用的信息。 %%% 这是对细胞色素c氧化酶亚基Ⅱ酵母蛋白遗传学研究的继续。 这种蛋白质是所有高等生物呼吸所需的高度保守蛋白质。 这项研究有可能扩大我们对呼吸的理解。 此外，该项目还为大学本科生提供了了解科学研究过程并参与其中的机会。

9317071 Cameron Subunit II of cytochrome c oxidase is a highly conserved protein required for respiration in all eucaryotes and some procaryotes. The enzyme complex is the terminal member of the electron transport chain responsible for transferring electrons from cytochrome c to oxygen. Subunit II binds to cytochrome c and accepts electrons via the CuA redox center. The protein has several highly conserved features including two hydrophobic regions, a conserved aromatic region, a number of negatively charged amino acids thought to interact with lysines on cytochrome c and a copper binding site like those found in blue copper proteins. To understand the function of this protein, yeast mutants defective in subunit II have been generated. We have identified strains defective in function due to alterations in the CuA binding region and due to codon substitutions in the aromatic region. We are finishing our analysis of the mutants and to extend our investigation to revertants of these strains that have recovered function. We expect to find true revertants that restore that wild type sequence; pseudo revertants where one amino acid is substituted for another and strains carrying extra- genic suppressors. Among the latter group, we expect to identify gene products, both nuclear and mitochondrial, that interact directly with subunit II. This analysis will yield information concerning functionally critical amino acids in the protein and possibly about interactions between oxidase subunits. %%% This is a continuation of the genetic studies on the yeast protein, subunit II of cytochrome c oxidase. This protein is a highly conserved protein required for respiration in all higher organisms. This research has the potential to broaden our understanding of respiration. In addition, the project is providing college undergraduates with the opportunity to understand the process of scientific research and to participate in it. ***