Structure of the torque ring of the flagellar motor and the molecular basis for rotational switching.
Structure of the torque ring of the flagellar motor and the molecular basis for rotational switching.
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作者：
鞭毛马达驱动鞭毛丝以每秒数百转的速度旋转，有效地推动细菌通过粘性介质。马达利用阳离子的电化学梯度产生的势能，穿过细胞质膜产生扭矩。从逆时针旋转到顺时针旋转的快速切换决定了细菌是平稳地向前移动，还是翻滚着改变其轨迹。一种叫做FliG的蛋白质在鞭毛马达的转子上形成一个环，通过与形成阳离子通道的定子亚基MotA的相互作用，参与产生扭矩，，，，，。FliG已被认为采用不同的构象来诱导开关，但这些结构变化和开关的分子机制尚不清楚。在这里，我们报道了全长FliG蛋白的分子结构，确定了参与旋转开关的构象变化，并揭示了FliG扭矩环形成的结构基础。这使我们能够提出一个完整的环和开关机制的模型，其中FliG的构象变化逆转了扭矩产生中涉及的静电荷。
The flagellar motor drives the rotation of flagellar filaments at hundreds of revolutions per second,, efficiently propelling bacteria through viscous media. The motor uses the potential energy from an electrochemical gradient of cations,across the cytoplasmic membrane to generate torque. A rapid switch from anticlockwise to clockwise rotation determines whether a bacterium runs smoothly forward or tumbles to change its trajectory,. A protein called FliG forms a ring in the rotor of the flagellar motor that is involved in the generation of torque,,,,,through an interaction with the cation-channel-forming stator subunit MotA. FliG has been suggested to adopt distinct conformations that induce switching but these structural changes and the molecular mechanism of switching are unknown. Here we report the molecular structure of the full-length FliG protein, identify conformational changes that are involved in rotational switching and uncover the structural basis for the formation of the FliG torque ring. This allows us to propose a model of the complete ring and switching mechanism in which conformational changes in FliG reverse the electrostatic charges involved in torque generation.
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影响因子：
64.8
作者：
LOWE, G;MEISTER, M;BERG, HC
通讯作者：
BERG, HC
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
BERG, HC;ANDERSON, RA
通讯作者：
ANDERSON, RA
影响因子：
3.2
作者：
Brown, Perry N.;Terrazas, Moises;Blair, David F.
通讯作者：
Blair, David F.
DOI：
10.1073/pnas.89.14.6304
发表时间：
1992-07-15
影响因子：
11.1
作者：
FRANCIS, NR;IRIKURA, VM;MACNAB, RM
通讯作者：
MACNAB, RM