Thermophilic ATP synthase has a decamer c-ring:: Indication of noninteger 10:3 H+/ATP ratio and permissive elastic coupling
Thermophilic ATP synthase has a decamer c-ring:: Indication of noninteger 10:3 H+/ATP ratio and permissive elastic coupling
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DOI：
10.1073/pnas.0403545101
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发表时间：
2004-08-17
影响因子：
11.1
通讯作者：
Yoshida, M
中科院分区：
文献类型：
--
作者：
Mitome, N;Suzuki, T;Yoshida, M
在将H+转运与ATIP合成/水解偶联的旋转马达FoF 1-ATP合酶中，认为膜中的F（o）c亚基寡聚物环（c环）随着质子通过F-o而旋转，并且120度旋转在F-1处产生一个ATP。尽管进行了几次结构研究，但尚未确定任何功能性FoF 1的C环中F（o）c亚基的拷贝数。在这里，我们已经产生并分离了嗜热芽孢杆菌FoF 1，每一种都含有基因融合的2-mer-14-mer c（c（2）-c（14））。其中，含有c（2）、c（5）或c（10）的FoF 1显示ATP合成和其它活性。当去除F-1时，含有c（10）的F-0作为H+通道起作用，而含有c（9）、c（11）或c（12）的F（o）s则不起作用。因此，该生物体的功能性FoF 1的C环是十聚体。这一发现的必然结果是F-1/F-o（120度/36度）和H+/ATP（10：3）的旋转步长的非整数比。这种阶跃失配使得在旋转期间转子轴（和/或侧杆）的弹性扭转以及通过在F-0处的H+运输的单元旋转与在F-1处的催化中的基本事件之间的容许耦合成为必要。
In a rotary motor FoF1-ATP synthase that couples H+ transport with ATIP synthesis/hydrolysis, it is thought that an F(o)c subunit oligomer ring (c-ring) in the membrane rotates as protons pass through F-o and a 120degrees rotation produces one ATP at F-1. Despite several structural studies, the copy number of F(o)c subunits in the c-ring has not been determined for any functional FoF1. Here, we have generated and isolated thermophilic Bacillus FoF1, each containing genetically fused 2-mer-14-mer c (c(2)-c(14)). Among them, FoF1 containing c(2), c(5), or c(10) showed ATP-synthesis and other activities. When F-1 was removed, F-o containing c(10) worked as an H+ channel but F(o)s containing c(9), c(11) or c(12) did not. Thus, the c-ring of functional FoF1 of this organism is a decamer. The inevitable consequence of this finding is noninteger ratios of rotation step sizes of F-1/F-o (120degrees/36degrees) and of H+/ATP (10:3). This step-mismatch necessitates elastic twisting of the rotor shaft (and/or the side stalk) during rotation and permissive coupling between unit rotations by H+ transport at F-o and elementary events in catalysis at F-1.