Journal
STRUCTURE
Volume 13, Issue 8, Pages 1107-1118Publisher
CELL PRESS
DOI: 10.1016/j.str.2005.05.005
Keywords
-
Funding
- NCRR NIH HHS [P41-RR05969] Funding Source: Medline
- NIGMS NIH HHS [R01-GM067887] Funding Source: Medline
Ask authors/readers for more resources
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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available