Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes
Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes
复制标题
从突触后膜图像重建乙酰胆碱受体的离子通道
作者：
C. Toyoshima;N. Unwin
烟碱乙酰胆碱受体属于一类对化学刺激作出短暂反应的分子，其通过打开穿过细胞膜的充满水的通道以使阳离子扩散。该通道沿着由五个同源的跨膜亚基1，2组成的环所描绘的中心轴，因此具有电导率和离子选择性等特性，这些特性取决于由环绕亚基产生的轮廓。最近已经获得了关于直接参与离子转运的氨基酸残基的见解3 -7，并且关于通道周围的亚基构型的一些信息来自于以扁平管状囊泡形式结晶的突触后膜的电子显微镜研究8 -11。然而，沿通道轴线的沿着分辨率受到可获得的有限视图范围的限制。在这里，我们报告的通道的结构在17 μ m的分辨率，确定的三维图像重建从管状囊泡有受体组织在其表面上的螺旋阵列。螺旋对称性通过将管悬浮在薄的冰膜中来保持，并且可以从各个角度看到这样的管中的受体，从而首次清楚地显示与脂质双层和外周蛋白质相关的通道。
The nicotinic acetylcholine receptor belongs to a class of molecules that respond transiently to chemical stimuli by opening a water-filled channel through the cell membrane for cations to diffuse. This channel lies along the central axis delineated by a ring of five homologous, membrane-spanning subunits1,2 and thus has properties, such as conductance and ion selectivity, which depend on the profile created by the encircling subunits. Insight has been gained recently about the amino-acid residues implicated directly in the ion transport3–7, and some information about the subunit configuration around the channel has come from electron micros-copy studies of postsynaptic membranes crystallized in the form of flattened tubular vesicles8–11. The resolution along the axis of the channel has, however, been limited by the restricted range of views obtainable. Here we report the structure of the channel at 17 Å resolution, determined by three-dimensional image recon-struction from tubular vesicles having receptors organized in helical arrays across their surfaces. The helical symmetry is preserved by suspending the tubes in thin films of ice, and the receptors in such tubes can be seen from all angles, allowing the channel to be revealed clearly in relation to the lipid bilayer and the peripheral protein for the first time.
与富含乙酰胆碱受体的膜相关的 Mr = 43,000 种蛋白质的表征和定位。
DOI：
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发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Porter,S;Froehner,SC
通讯作者：
Froehner,SC