The F1F0-ATPase complex from bovine heart mitochondria: The molar ratio of the subunits in the stalk region linking the F-1 and F-0 domains
The F1F0-ATPase complex from bovine heart mitochondria: The molar ratio of the subunits in the stalk region linking the F-1 and F-0 domains
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DOI：
10.1021/bi960969t
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发表时间：
1996-09-24
期刊：
影响因子：
2.9
通讯作者：
Walker, JE
中科院分区：
文献类型：
--
作者：
Collinson, IR;Skehel, JM;Walker, JE
在细菌、叶绿体和线粒体中的F1 Fo-ATP酶的F-1球状催化结构域和F-0内在膜结构域通过细长柄连接。在来自牛心脏线粒体的F1 Fo复合物中，认为柄包含亚基OSCP、d和F-6，以及膜结合亚基B的球状部分，称为b '。先前已经表明，OSCP、b '、d和F-6蛋白可以在体外组装成称为“茎”的水溶性复合物。茎和F-1-ATP酶一起形成另一个复合物，称为F-1。茎本文研究了OSCP、B（或b '）、d和F-6在秸秆、F-1 .茎，和F1 Fo-ATPase复合物已通过三种独立的方法进行了研究。通过用碘-2-[（14）]乙酸进行S-羧甲基化，将放射性掺入到含有突变Glu（3）-Cys的F-6形式的茎复合物中，通过对放射性进行定量，表明茎由等摩尔量的四种组成蛋白质组成。在含有天然F-6序列的茎复合物中，通过用[1-C-14]乙酰亚胺酸乙酯进行N-乙酰亚胺化而掺入的放射性的定量以及亚基的定量N-末端序列分析证实了这一结论。通过类似的N-乙酰亚胺化实验，已经证明F-1 .茎复合物含有OSCP、b ′、d和F-6蛋白质的每个组装体的一个拷贝，F1 Fo-ATPase含有亚基OSCP、B和d的每个酶复合物的一个拷贝。F-1中每个OSCP、B'（或B）、d和F-6蛋白复合物存在一个拷贝。茎和F1 Fo-ATP酶复合物，分别通过定量测序确认。
The F-1 globular catalytic domain and the F-o intrinsic membrane domain of the F1Fo-ATPases in bacteria, chloroplasts, and mitochondria are connected by a slender stalk. In the F1Fo complex from bovine heart mitochondria, the stalk is thought to contain subunits OSCP, d, and F-6, and the globular part of the membrane bound subunit b, referred to as b'. It has been shown previously that the OSCP, b', d, and F-6 proteins can be assembled in vitro into a water soluble complex named the ''stalk''. The stalk and F-1-ATPase together form another complex named F-1 . stalk. In this paper, the molar ratios of the OSCP, b (or b'), d, and F-6 in the stalk, F-1 . stalk, and F1Fo-ATPase complexes have been investigated by three independent methods. By quantitation of radioactivity incorporated by S-carboxymethylation with iodo-2-[(14)]acetic acid into a stalk complex containing a form of F-6 With the mutation Glu(3)-Cys, it was shown that the stalk consists of equimolar quantities of its four constituent proteins. In the stalk complex containing the natural F-6 sequence, this conclusion was confirmed both by quantitation of radioactivity incorporated by N-epsilon-acetimidation with ethyl [1-C-14]acetimidate, and by quantitative N-terminal sequence analysis of subunits. By similar N-epsilon-acetimidation experiments, it has been demonstrated that the F-1 . stalk complex contains one copy per assembly of the OSCP, b', d, and F-6 proteins and that the F1Fo-ATPase contains one copy per enzyme complex of subunits OSCP, b, and d. The presence of one copy per complex of the OSCP, b' (or b), d, and F-6 proteins in the F-1 . stalk and F1Fo-ATPase complexes, respectively, was confirmed by quantitative sequencing.