Structural basis for conductance by the archaeal aquaporin AqpM at 1.68 Å
Structural basis for conductance by the archaeal aquaporin AqpM at 1.68 Å
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DOI：
10.1073/pnas.0509469102
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发表时间：
2005-12-27
影响因子：
11.1
通讯作者：
Stroud, RM
中科院分区：
文献类型：
--
作者：
Lee, JK;Kozono, D;Stroud, RM
为了探索古甲烷热细菌Marburgensis跨膜通道蛋白AqpM独特的选择性光谱和电导的结构基础，我们用X射线结晶学测定了AqpM的结构，分辨率为1.68-A。这种结构将AqpM确定为水通道蛋白的两个主要亚类之间的一个独特的细分，即水选择性水通道蛋白和水+甘油传导水甘油通道蛋白。在AqpM中，异亮氨酸取代了在水通道管腔中发现的关键组氨酸残基，它成为水甘油通透性蛋白中的甘氨酸残基。由于通道壁上的这个和其他侧链取代基，通道的大小是中等的，并且与其他亚家族相比表现出不同的调谐静电。
To explore the structural basis of the unique selectivity spectrum and conductance of the transmembrane channel protein AqpM from the archaeon Methanothermobacter marburgensis, we determined the structure of AqpM to 1.68-A resolution by x-ray crystallography. The structure establishes AqpM as being in a unique subdivision between the two major subdivisions of aquaporins, the water-selective aquaporins, and the water-plus-glycerol-conducting aquaglyceroporins. In AqpM, isoleucine replaces a key histidine residue found in the lumen of water channels, which becomes a glycine residue in aquaglyceroporins. As a result of this and other side-chain substituents in the walls of the channel, the channel is intermediate in size and exhibits differentially tuned electrostatics when compared with the other subfamilies.