BIOSYNTHESIS OF CYTOCHROME OXIDASE

细胞色素氧化酶是一种重要的结构和功能成分。 线粒体内膜。因此，它已成为一种模型酶 研究了电子输运和能量耦合的机理。在……里面 此外，它非常适合于探索与生物合成有关的问题。 和完整膜蛋白的组装。在酵母中，细胞色素氧化酶 由七种不同的亚基多肽组成。最大的三个 亚单位在内部由线粒体翻译而成 系统。功能尚不清楚的四个较小的亚基是 已知是细胞体蛋白质合成的产物。双重起源 也反映在编码该酶的基因的位置 结构构件。酵母菌的遗传和物理分析 线粒体DNA揭示了内部合成的亚基 也编码在细胞器基因组中。他们的基因已经被测序 并精确地绘制在基因组上。 尽管最近在定义企业的贡献方面取得了重大进展 线粒体遗传系统，生物合成的许多重要方面 这种酶目前还不清楚。关于这一点的信息很少 核DNA中的结构基因和调控元件影响 细胞色素氧化酶的表达。本申请包括两个 研究的一般领域。第一个将试图利用最近的一个 获得的酵母核呼吸缺陷突变体的收集 确定细胞色素表达所需的一组基因 氧化物酶。编码结构亚单位的基因将被克隆并 对它们的序列进行检查，以寻找可能的共同调控特征。 其次，线粒体和核突变体在细胞色素氧化酶中存在缺陷 将被用来研究导致宇宙形成的事件序列 功能性全酶。

Cytochrome oxidase is an important structural and functional constituent of the mitochondrial inner membrane. As such it has become a model enzyme for studies on the mechanism of electron transport and energy coupling. In addition, it is well suited to probe questions related to the biosynthesis and assembly of integral membrane proteins. In yeast, cytochrome oxidase is composed of seven different subunit polypeptides. The three largest subunits are synthesized internally by the mitochondrial translational system. The four smaller subunits whose functions are still unclear, are known to be products of cytoribosomal protein synthesis. The dual origin of the enzyme is also reflected in the location of the genes coding for the structural components. Genetic and physical analyses of yeast mitochondrial DNA have revealed that the internally synthesized subunits are also encoded in the organellar genome. Their genes have been sequenced and precisely mapped on the genome. Despite the significant recent advances in defining the contribution of the mitochondrial genetic system, many important aspects of the biosynthesis of this enzyme remain unclear. Very little information exists concerning the structural genes and regulatory elements in nuclear DNA that influence the expression of cytochrome oxidase. The present application encompasses two general areas of studies. The first will attempt to exploit a recently acquired collection of nuclear respiratory deficient mutants of yeast to identify the set of genes required for the expression of cytochrome oxidase. The genes coding for the structural subunits will be cloned and their sequences examined for possible common regulatory features. Secondly, mitochondrial and nuclear mutants defective in cytochrome oxidase will be used to study the sequence of events leading to the formation of the functional holoenzyme.