Stoichiometry and deletion analyses of subunits in the heterotrimeric F-ATP synthase c ring from the acetogenic bacterium Acetobacterium woodii
Stoichiometry and deletion analyses of subunits in the heterotrimeric F-ATP synthase c ring from the acetogenic bacterium Acetobacterium woodii
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DOI：
10.1111/febs.13606
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发表时间：
2016-02-01
期刊：
影响因子：
5.4
通讯作者：
Mueller, Volker
中科院分区：
文献类型：
--
作者：
Brandt, Karsten;Mueller, Daniel B.;Mueller, Volker
厌氧细菌伍氏醋杆菌的 Na+ F1Fo ATP 合酶的离子易位 c 环是自然界中发现的第一个异聚 c 环，包含一个 V- (c(1)) 和两个 F 型 c 亚基 (c(2)/c(3))，后者具有相同的氨基酸序列。为了解决它们对于功能的重要性是否相同或不同，它们被组合或单独删除。 c(1) 的缺失通过掺入两个 c(2)/c(3) 亚基来补偿，但该酶不稳定且 Na+ 转运受到严重损害。 c(2) 的缺失通过 c(3) 的掺入得到补偿，但也导致 Na+ 转运减少。删除 c(3) 没有效果。相反，c(2) 和 c(3) 的缺失导致细胞质膜 ATP 酶活性完全丧失。 c(2)+1 Ala 和 c(2)+2 Ala 变体的质谱分析显示 c(2)/c(3) 的拷贝数为 8:1，这与变体的生化特征一致。这些数据表明 c(1) 在组装中的作用以及 c(2) 作为主要 c 环成分的功能。
The ion-translocating c ring of the Na+ F1Fo ATP synthase of the anaerobic bacterium Acetobacterium woodii is the first heteromeric c ring found in nature that contains one V- (c(1)) and two F-type-like c subunits (c(2)/c(3)), the latter of identical amino acid sequence. To address whether they are of equal or different importance for function, they were deleted in combination or individually. Deletion of c(1) was compensated by incorporation of two c(2)/c(3) subunits but the enzyme was unstable and largely impaired in Na+ transport. Deletion of c(2) was compensated by incorporation of c(3) but also led to a reduction of Na+ transport. Deletion of c(3) had no effect. In contrast, deletion of both c(2) and c(3) led to a complete loss of ATPase activity at the cytoplasmic membrane. Mass spectrometric analysis of c(2)+1 Ala and c(2)+2 Ala variants revealed a copy number of 8 : 1 for c(2)/c(3) which is consistent with the biochemical characteristics of the variants. These data indicate a role of c(1) in assembly and a function of c(2) as the predominant c ring constituent.