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Mutual Recognition and Electron Transfer of Electron Carriers: Cytochrome and Ferredoxin Systems

电子载体的相互识别和电子转移：细胞色素和铁氧还蛋白系统

基本信息

批准号：
60470156
负责人：
MATSUBARA Hiroshi
金额：
$ 3.58万
依托单位：
Faculty of Science, Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

The cytochrome <C_1> subcomplex of beef heart mitochondria was reacted with 3 molar equivalents of pCMB to modify 3 SH-groups. The two subunits (heme-subunit and hinge protein) were not separated on gel filtration, but by electrophoresis after this treatment, leading to the appearance of autoxidizability of <C_1> heme subunit. This indicates that the hinge protein is indispensable not only for complex formation between <C_1> and c, but also for obstructing the <C_1> heme subunit from autoxidation. The heme subunit seems to polymerize if the hinge protein is not associated.Some mutated genes of cytochrome <C_1> were introduced into yeast cells to see how they affect the growth of yeast, respiratory ability, spectral characteristics, assembly into mitochondrial inner membrane, and gene expression. The deletion of 17 amino acids from the carboxyl-terminal region of <C_1> did not affect at all these characteristics, but when 70 amino acids from the carboxyl-terminal region were deleted, the protein modified lost the ability to be integrated into complex III of respiratory chain, and growth as well as respiration. This was partly predicted when the structure of beef cytochrome <C_1> was established. The work on this line is very promising to elucidate structure-function relationship of not only cytochrome <C_1> , but other membranous proteins. Other works done during this term are as follows: Identification of the heme iron ligands, crystallizations of <C_1> and ferredoxin <NADP^+> reductase, characterization of SH-groups in this enzyme, and iron-sulfur cluster formation.

牛心线粒体的细胞色素<C_1>亚复合物与3摩尔当量的pCMB反应，修饰3个SH-基团。这两个亚基（血红素亚基和铰链蛋白）没有分离的凝胶过滤，但电泳后，这种处理，导致出现的血红素亚基的自氧化能力<C_1>。这表明，铰链蛋白不仅是必不可少的复合物之间的形成<C_1>和c，但也为阻止<C_1>血红素亚基自氧化。将细胞色素的一些突变基因<C_1>导入酵母细胞，观察它们如何影响酵母的生长、呼吸能力、光谱特性、组装到线粒体内膜以及基因表达。从羧基末端区域的17个氨基酸的缺失<C_1>并没有影响在所有这些特性，但当从羧基末端区域的70个氨基酸被删除，修饰的蛋白质失去的能力，被整合到呼吸链的复合体III，生长以及呼吸。这在牛肉细胞色素结构确定时就已部分预测到<C_1>。这一工作不仅对细胞色素，而且对其它膜蛋白的结构与功能关系的研究都具有重要意义<C_1>。在这一学期中完成的其他工作如下：血红素铁配体的鉴定，铁氧还<C_1>蛋白<NADP^+>还原酶的结晶，该酶中SH基团的表征，以及铁硫簇的形成。