期刊
STRUCTURE
卷 13, 期 8, 页码 1107-1118出版社
CELL PRESS
DOI: 10.1016/j.str.2005.05.005
关键词
-
资金
- NCRR NIH HHS [P41-RR05969] Funding Source: Medline
- NIGMS NIH HHS [R01-GM067887] Funding Source: Medline
The recent availability of high-resolution structures of two structurally highly homologous, but functionally distinct aquaporins from the same species, namely Escherichia coli AqpZ, a pure water channel, and GIpF, a glycerol channel, presents a unique opportunity to understand the mechanism of substrate selectivity in these channels. Comparison of the free energy profile of glycerol conduction through AqpZ and GIpF reveals a much larger barrier in AqpZ (22.8 kcal/ mol) than in GlpF (7.3 kcal/mol). In either channel, the highest barrier is located at the selectivity filter. Analysis of substrate-protein interactions suggests that steric restriction of AqpZ is the main contribution to this large barrier. Another important difference is the presence of a deep energy well at the periplasmic vestibule of GIpF, which was not found in AqpZ. The latter difference can be attributed to the more pronounced structural asymmetry of GIpF, which may play a role in attracting glycerol.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据