Rhee Kyong-Hi, Scarborough Gene A, Henderson Richard
MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
EMBO J. 2002 Jul 15;21(14):3582-9. doi: 10.1093/emboj/cdf385.
H(+)-ATPase is a P-type ATPase that transports protons across membranes using the energy from ATP hydrolysis. This hydrolysis is coupled to a conformational change between states of the protein, in which the proton-binding site is alternately accessible to the two sides of the membrane with an altered affinity. When isolated from Neurospora crassa, H(+)-ATPase is a 600 kDa hexamer of identical 100 kDa polypeptides. We have obtained the three-dimensional structures of both ligand-free and Mg(2+)/ADP-bound states of this complex using single-particle electron cryo- microscopy. Structural comparisons, together with the difference map, indicate that there is a rearrangement of the cytoplasmic domain on Mg(2+)/ADP binding, which consists of a movement of mass towards the 6-fold axis causing the structure to become more compact, accompanied by a modest conformational change in the transmembrane domain.
H(+)-ATP酶是一种P型ATP酶，它利用ATP水解产生的能量跨膜转运质子。这种水解与蛋白质不同状态之间的构象变化相偶联，在此过程中，质子结合位点以不同的亲和力交替暴露于膜的两侧。从粗糙脉孢菌中分离出来时，H(+)-ATP酶是由相同的100 kDa多肽组成的600 kDa六聚体。我们使用单颗粒冷冻电子显微镜获得了该复合物无配体状态和Mg(2+)/ADP结合状态的三维结构。结构比较以及差分图表明，Mg(2+)/ADP结合时细胞质结构域会发生重排，即质量向六重轴移动，导致结构变得更加紧凑，同时跨膜结构域也会发生适度的构象变化。
