Rotatory catalysis by F-ATPase: Real-time recording of intersubunit rotation

被引:47
作者
Junge, W
Sabbert, D
Engelbrecht, S
机构
来源
BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 1996年 / 100卷 / 12期
关键词
biophysical chemistry; catalysis; diffusion; molecular structure; protein dynamics (molecular dynamics);
D O I
10.1002/bbpc.19961001215
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
ATP synthase (F-ATPase) is an ubiquitous enzyme in photosynthesis and respiration of prokaryotic and eukaryotic organisms. It couples proton translocation through its membrane portion, F-0, to the synthesis of the ''energy carrier molecule'' ATP at the peripheral portion, F-1 [1]. Three cooperative reaction sites are distributed with trigonal symmetry over the hexagonal array of (alpha beta)(3) in F-1 [2, 3]. It has been proposed that the endergonic release of spontaneously formed ATP [4, 5] might involve mechanical energy transduction [6, 7] through the proton driven rotation of subunit gamma within (alpha beta)(3) [2, 8, 9]. We recorded the putative intersubunit rotation in real rime [10]. Applying polarized absorption relaxation after photobleaching (PARAP) to immobilized F-1 with eosinlabeled gamma, we observed the rotational motion of gamma relative to immobilized (alpha beta)(3) in the time range of 100 ms, compatible with the rate of ATP hydrolysis by immobilized F-1. Its angular domain of at least 200 degrees favours a rotatory tri-site mechanism of catalysis with gamma acting as a crankshaft in the center of (alpha beta)(3).
引用
收藏
页码:2014 / 2019
页数:6
相关论文
共 40 条