Three-dimensional structure of a recombinant gap junction membrane channel
Three-dimensional structure of a recombinant gap junction membrane channel
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DOI：
10.1126/science.283.5405.1176
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发表时间：
1999-02-19
期刊：
影响因子：
56.9
通讯作者：
Yeager, M
中科院分区：
文献类型：
--
作者：
Unger, VM;Kumar, NM;Yeager, M
间隙连接膜通道介导相邻细胞之间的电和代谢耦合。利用电子晶体技术，在膜平面分辨率为7.5埃，在垂直方向分辨率为21埃的情况下，对重组心脏间隙连接通道的结构进行了研究。十二聚体通道是由两个六聚体端到端对接形成的，每个六聚体在膜内部显示24棒的密度，这与每个连接蛋白亚基的四个跨膜结构域的α -螺旋构象一致。跨膜的α -螺旋棒与双层胞外结构域形成对比。虽然不能说明一种特殊类型的二级结构，但形成细胞外前庭的蛋白质密度提供了一个紧密的密封，以排除与细胞外环境的物质交换。
Gap junction membrane channels mediate electrical and metabolic coupling between adjacent cells. The structure of a recombinant cardiac gap junction channel was determined by electron crystallography at resolutions of 7.5 angstroms in the membrane plane and 21 angstroms in the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which is consistent with an alpha-helical conformation for the four transmembrane domains of each connexin subunit. The transmembrane alpha-helical rods contrasted with the double-layered appearance of the extracellular domains. Although not indicative for a particular type of secondary structure, the protein density that formed the extracellular vestibule provided a tight seal to exclude the exchange of substances with the extracellular milieu.