Dodecamer rotor ring defines H+/ATP ratio for ATP synthesis of prokaryotic V-ATPase from Thermus thermophilus
Dodecamer rotor ring defines H+/ATP ratio for ATP synthesis of prokaryotic V-ATPase from Thermus thermophilus
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DOI：
10.1073/pnas.0706914105
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发表时间：
2007-12-18
影响因子：
11.1
通讯作者：
Yokoyama, Ken
中科院分区：
文献类型：
--
作者：
Toei, Masashi;Gerle, Christoph;Yokoyama, Ken
研究了嗜热菌Thermus thermophilus在酸碱转换驱动下利用V-ATPase合成ATP的过程。ATP合成速率的增加与>110 mV的质子动力（PMF）的增加平行，所述质子动力（PMF）由跨膜的质子浓度差（Δ pH）和电势差（Δ Psi）组成。最佳合成速率为85 s（-1），H+/ATP比为4.0 +/-0.1。ATP的合成在相当大的速度仅由Δ pH，表明Δ Psi不是绝对需要的合成。与H+/ATP比率一致，在7.0埃分辨率下的V-ATP酶的膜结合转子环的2D晶体的冷冻电子显微照片图像显示存在12个V-o-c亚基，每个亚基由两个跨膜螺旋组成。这些结果表明，转子和催化结构域之间的对称性不匹配不是强制性的旋转ATP酶/ATP酶。
ATP synthesis by V-ATPase from the thermophilic bacterium Thermus thermophilus driven by the acid-base transition was investigated. The rate of ATP synthesis increased in parallel with the increase in proton motive force (PMF) >110 mV which is composed of a difference in proton concentration (Delta pH) and the electrical potential differences (Delta Psi) across membranes. The optimum rate of synthesis reached 85 s(-1), and the H+/ATP ratio of 4.0 +/- 0.1 was obtained. ATP was synthesized at a considerable rate solely by Delta pH, indicating Delta Psi was not absolutely required for synthesis. Consistent with the H+/ATP ratio, cryoelectron micrograph images of 2D crystals of the membrane-bound rotor ring of the V-ATPase at 7.0-angstrom resolution showed the presence of 12 V-o-c subunits, each composed of two transmembrane helices. These results indicate that symmetry mismatch between the rotor and catalytic domains is not obligatory for rotary ATPases/synthases.