Unwin N
MRC Laboratory of Molecular Biology, Cambridge, UK.
Nature. 1995 Jan 5;373(6509):37-43. doi: 10.1038/373037a0.
The structure of the open-channel form of the acetylcholine receptor has been determined from electron images of Torpedo ray postsynaptic membranes activated by brief (< 5 ms) mixing with droplets containing acetylcholine. Comparison with the closed-channel form shows that acetylcholine initiates small rotations of the subunits in the extracellular domain, which trigger a change in configuration of alpha-helices lining the membrane-spanning pore. The open pore tapers towards the intracellular membrane face, where it is shaped by a 'barrel' of alpha-helices having a pronounced right-handed twist.
通过将电鳐突触后膜与含有乙酰胆碱的液滴短暂混合（<5毫秒）激活后所获得的电子图像，已确定了乙酰胆碱受体开放通道形式的结构。与关闭通道形式的比较表明，乙酰胆碱引发了细胞外结构域中亚基的微小旋转，这触发了跨膜孔内衬α螺旋构象的变化。开放的孔向细胞内膜表面逐渐变窄，在那里它由具有明显右手扭曲的α螺旋“桶”形成形状。
