Aquaporin-0 membrane junctions reveal the structure of a closed water pore
Aquaporin-0 membrane junctions reveal the structure of a closed water pore
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DOI：
10.1038/nature02503
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发表时间：
2004-05-13
期刊：
影响因子：
64.8
通讯作者：
Walz, T
中科院分区：
文献类型：
--
作者：
Gonen, T;Sliz, P;Walz, T
晶状体特异性水孔水通道蛋白-0（AQP 0）是已知在体内形成膜连接的唯一水通道蛋白（1）。我们在这里表明，水通道蛋白0从透镜核心，含有一些羧基末端裂解水通道蛋白0（2，3），形成双层晶体，重现在体内的交界处。我们展示了通过电子晶体学确定的AQP 0膜结合部的结构。该连接是由相邻膜中AQP 0分子之间的三种局部相互作用形成的，主要由不同物种AQP 0中保守的脯氨酸残基介导，但不存在于大多数其他水通道蛋白中。尽管所有先前确定的水通道蛋白结构显示孔处于开放构象（4-9），但水孔在AQP 0连接处是封闭的。AQP 0中的水通路还包含额外的孔收缩，这在其他已知的水通道蛋白结构中未见（4-9），其可能负责孔门控。
The lens-specific water pore aquaporin-0 (AQP0) is the only aquaporin known to form membrane junctions in vivo(1). We show here that AQP0 from the lens core, containing some carboxy-terminally cleaved AQP0(2,3), forms double-layered crystals that recapitulate in vivo junctions. We present the structure of the AQP0 membrane junction as determined by electron crystallography. The junction is formed by three localized interactions between AQP0 molecules in adjoining membranes, mainly mediated by proline residues conserved in AQP0s from different species but not present in most other aquaporins. Whereas all previously determined aquaporin structures show the pore in an open conformation(4-9), the water pore is closed in AQP0 junctions. The water pathway in AQP0 also contains an additional pore constriction, not seen in other known aquaporin structures(4-9), which may be responsible for pore gating.