期刊
BIOPHYSICAL JOURNAL
卷 90, 期 11, 页码 4195-4203出版社
CELL PRESS
DOI: 10.1529/biophysj.105.079087
关键词
-
类别
F-1-ATPase is an ATP-driven rotary molecular motor in which the central gamma-subunit rotates inside a stator cylinder made of alpha(3)beta(3) subunits. To elucidate the role of rotor-stator interactions in torque generation, we truncated the gamma-subunit at its carboxyl terminus, which forms an a helix that penetrates deeply into the stator cylinder. We used an alpha(3)beta(3)gamma subcomplex of F-1-ATPase derived from thermophilic Bacillus PS3 and expressed it in Escherichia coli. We could obtain purified subcomplexes in which 14, 17, or 21 amino-acid residues were deleted. The rotary characteristics of the truncated mutants, monitored by attaching a duplex of 0.49-mu m beads to the gamma-subunit, did not differ greatly from those of the wild-type over the ATP concentrations of 20 nM-2 mM, the most conspicuous effect being; 50% reduction in torque and; 70% reduction in the rate of ATP binding upon deletion of 21 residues. The ATP hydrolysis activity estimated in bulk samples was more seriously affected. The 21-deletion mutant, in particular, was > 10-fold less active, but this is likely due to instability of this subcomplex. For torque generation, though not for rapid catalysis, most of the rotor-stator contacts on the deeper half of the penetrating portion of the gamma-subunit are dispensable.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据