Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
FEBS Lett. 2013 Apr 2;587(7):989-93. doi: 10.1016/j.febslet.2013.02.038. Epub 2013 Feb 27.
Plants have evolved to cope with fluctuations in water supply by gating their water channels known as aquaporins. During flooding, a rapid drop of cytosolic pH due to anoxia leads to a simultaneous closure of the aquaporins in the plasma membrane. The closing mechanism has been suggested to involve a conserved histidine on cytosolic loop D. Here we report the crystal structure of a spinach aquaporin at low pH, revealing for the first time the structural basis for how this pH-sensitive histidine helps to keep the aquaporin in a closed state.
植物通过调控其水通道蛋白（Aquaporins）来适应供水的波动。在洪水期间，由于缺氧导致细胞质 pH 值迅速下降，从而导致质膜中的水通道蛋白同时关闭。关闭机制被认为涉及细胞质环 D 上的保守组氨酸。在这里，我们报告了菠菜水通道蛋白在低 pH 值下的晶体结构，首次揭示了这种 pH 敏感的组氨酸如何帮助水通道蛋白保持关闭状态的结构基础。
