Mechanism for adaptive remodeling of the bacterial flagellar switch
Mechanism for adaptive remodeling of the bacterial flagellar switch
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DOI：
10.1073/pnas.1212327109
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发表时间：
2012-12-04
影响因子：
11.1
通讯作者：
Berg, Howard C.
中科院分区：
文献类型：
--
作者：
Lele, Pushkar P.;Branch, Richard W.;Berg, Howard C.
细菌鞭毛马达已经在以前的工作中被证明通过改变薄膜含量来适应趋化信号分子Chey-P的稳态浓度的变化。我们在这里表明，发动机中的薄膜分子的数量和交换的薄膜分子的比例取决于鞭毛旋转的方向，而不是取决于Chey-P结合本身。我们的结果与一个模型一致，在该模型中，与旋转方向相关的结构差异调节了薄膜结合的强度。当电机逆时针旋转时，薄膜结合加强，交换的薄膜分子比例减少，环含量增加。Chey-P结合位点的数量越多，马达的敏感度越高，即马达适应能力越强。一个有趣的悬而未决的问题是，如何容纳更多的电影拷贝。
The bacterial flagellar motor has been shown in previous work to adapt to changes in the steady-state concentration of the chemotaxis signaling molecule, CheY-P, by changing the FliM content. We show here that the number of FliM molecules in the motor and the fraction of FliM molecules that exchange depend on the direction of flagellar rotation, not on CheY-P binding per se. Our results are consistent with a model in which the structural differences associated with the direction of rotation modulate the strength of FliM binding. When the motor spins counterclockwise, FliM binding strengthens, the fraction of FliM molecules that exchanges decreases, and the ring content increases. The larger number of CheY-P binding sites enhances the motor's sensitivity, i.e., the motor adapts. An interesting unresolved question is how additional copies of FliM might be accommodated.