通过固态NMR光谱检测发现合成膜和原生膜中的Aquaporin Z的门机制
Yongxiang Zhao1,2, Huayong Xie1,2, Lili Wang3,4
1National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics , Chinese Academy of Sciences , Wuhan 430071 , P.R. China.
Journal of the American Chemical Society
|May 26, 2018
概括
之前被认为是水流门的Aquaporin Z的R189残留物,实际上是在原生膜中永久开放的状态. 固态核磁共振和结构分析证实了这一点,澄清了水素门机制.
科学领域:
- 膜蛋白的结构和功能
- 生物物理
- 结构生物学
背景情况:
- 水素Z (AqpZ) 促进大肠杆菌的快速水运输.
- 根据相互矛盾的结构和模拟数据,AqpZ的选择性过器中的R189残留物被假设作为一个门.
- 由于来自非原生环境的潜在文物,AqpZ的精确封闭机制,特别是R189的作用仍然存在争议.
研究的目的:
- 在本地类似的环境中研究Aquaporin Z (AqpZ) 的R189侧链的封闭机制.
- 解决有关R189残留物的结构状态和动态的争议.
- 阐明脂质双层在确定AqpZ的功能状态中的作用.
主要方法:
- 固态核磁共振 (NMR) 技术,包括2D 15N-13C光谱和1H-15N双极线形.
- 使用实验距离限制的CS-Rosetta计算来确定高分辨率的单体结构.
- 水的可访问性测试和水的透性实验.
主要成果:
- 固态NMR数据显示R189侧链的单一稳定构造,表明不移动,不包括快速构造切换.
- 通过CS-Rosetta的结构计算和水准测量,证实R189采用了开放形状.
- 综合的实验结果表明,在合成双层和本地大肠杆菌膜中,R189侧链的永久开放状态.
结论:
- 在原生类脂质环境中,Aquaporin Z 的 R189 侧链是构成性开放的,这挑战了之前的封闭假设.
- 这项研究强调了原生脂质双层环境对于精确确定膜蛋白的分子机制的重要性.
- 提供了对水素门和功能的新结构洞察力,强调了膜环境的影响.
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