Häsler K, Engelbrecht S, Junge W
Dept. Biology/Chemistry, Universität Osnabrück, Germany.
FEBS Lett. 1998 Apr 24;426(3):301-4. doi: 10.1016/s0014-5793(98)00358-5.
The proton translocating ATP synthase is conceived as a rotatory molecular engine. ATP hydrolysis by its headpiece, CF1, drives the rotation of subunit gamma relative to the hexagonally arranged large subunits, (alphabeta)3. We investigated transition states of the rotatory drive by polarized confocal fluorometry (POCOF) as applied to single molecules of engineered, immobilized and load-free spinach-CF1. We found that the hydrolysis of ATP caused the stepped and sequential progression of subunit gamma through three discrete angular positions, with the transition states of gamma being too shortlived for detection. We also observed the stepped motion of epsilon, whereas delta was immobile as (alphabeta)3.
质子转运ATP合酶被认为是一种旋转分子发动机。其头部CF1进行的ATP水解驱动γ亚基相对于六边形排列的大亚基（αβ）3旋转。我们通过偏振共聚焦荧光测定法（POCOF）研究了旋转驱动的过渡态，该方法应用于工程化、固定且无负载的菠菜CF1单分子。我们发现ATP水解导致γ亚基通过三个离散角度位置进行阶梯式连续推进，γ亚基的过渡态寿命过短而无法检测。我们还观察到ε亚基的阶梯式运动，而δ亚基则像（αβ）3一样静止不动。
