The alpha-helix and the organization and gating of channels.
The alpha-helix and the organization and gating of channels.
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发表时间：
2002
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通讯作者：
R. Spencer;D. Rees
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作者：
R. Spencer;D. Rees
最近，越来越多的通道和其他α-螺旋膜蛋白的结构被确定，包括KCSA钾通道，MSCL机械敏感通道，水通道蛋白家族的AQP1和GlpF成员。在本章中，我们综述了完整膜蛋白中双层螺旋的取向和堆积特性。在通道的情况下，α螺旋创建了密封的屏障，将双层的碳氢化合物区域与溶质的渗透路径分开。围绕着渗透途径的螺旋相对于正常的膜倾向于相当陡峭的倾斜，并且一致地排列在右手束中。螺旋骨架还为与通道选择性相关的非跨膜结构提供支撑支架。尽管结构细节仍然很少，但综述了与通道闭合和开放状态之间的门控转换相关的构象变化，强调了螺旋-螺旋相互作用在这一过程中的潜在作用。
The structures of an increasing number of channels and other alpha-helical membrane proteins have been determined recently, including the KcsA potassium channel, the MscL mechanosensitive channel, and the AQP1 and GlpF members of the aquaporin family. In this chapter, the orientation and packing characteristics of bilayer-spanning helices are surveyed in integral membrane proteins. In the case of channels, alpha-helices create the sealed barrier that separates the hydrocarbon region of the bilayer from the permeation pathway for solutes. The helices surrounding the permeation pathway tend to be rather steeply tilted relative to the membrane normal and are consistently arranged in a right-handed bundle. The helical framework further provides a supporting scaffold for nonmembrane-spanning structures associated with channel selectivity. Although structural details remain scarce, the conformational changes associated with gating transitions between closed and open states of channels are reviewed, emphasizing the potential roles of helix-helix interactions in this process.