Water channel pore size determines exclusion properties but not solute selectivity
(2019) In Scientific Reports 9(1).- Abstract
Aquaporins (AQPs) are a ubiquitous family of transmembrane water channel proteins. A subgroup of AQP water channels also facilitates transmembrane diffusion of small, polar solutes. A constriction within the pore, the aromatic/arginine (ar/R) selectivity filter, is thought to control solute permeability: previous studies on single representative water channel proteins suggest narrow channels conduct water, whilst wider channels permit passage of solutes. To assess this model of selectivity, we used mutagenesis, permeability measurements and in silico comparisons of water-specific as well as glycerol-permeable human AQPs. Our studies show that single amino acid substitutions in the selectivity filters of AQP1, AQP4 and AQP3... (More)
Aquaporins (AQPs) are a ubiquitous family of transmembrane water channel proteins. A subgroup of AQP water channels also facilitates transmembrane diffusion of small, polar solutes. A constriction within the pore, the aromatic/arginine (ar/R) selectivity filter, is thought to control solute permeability: previous studies on single representative water channel proteins suggest narrow channels conduct water, whilst wider channels permit passage of solutes. To assess this model of selectivity, we used mutagenesis, permeability measurements and in silico comparisons of water-specific as well as glycerol-permeable human AQPs. Our studies show that single amino acid substitutions in the selectivity filters of AQP1, AQP4 and AQP3 differentially affect glycerol and urea permeability in an AQP-specific manner. Comparison between in silico-calculated channel cross-sectional areas and in vitro permeability measurements suggests that selectivity filter cross-sectional area predicts urea but not glycerol permeability. Our data show that substrate discrimination in water channels depends on a complex interplay between the solute, pore size, and polarity, and that using single water channel proteins as representative models has led to an underestimation of this complexity.
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- author
- Kitchen, Philip ; Salman, Mootaz M. ; Pickel, Simone U. ; Jennings, Jordan ; Törnroth-Horsefield, Susanna LU ; Conner, Matthew T. ; Bill, Roslyn M. and Conner, Alex C.
- organization
- publishing date
- 2019
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Scientific Reports
- volume
- 9
- issue
- 1
- article number
- 20369
- publisher
- Nature Publishing Group
- external identifiers
-
- scopus:85077182633
- pmid:31889130
- ISSN
- 2045-2322
- DOI
- 10.1038/s41598-019-56814-z
- language
- English
- LU publication?
- yes
- id
- 08396163-cde1-4478-8ccb-7add8055473b
- date added to LUP
- 2020-01-10 14:06:33
- date last changed
- 2024-05-29 06:56:36
@article{08396163-cde1-4478-8ccb-7add8055473b,
abstract = {{<p>Aquaporins (AQPs) are a ubiquitous family of transmembrane water channel proteins. A subgroup of AQP water channels also facilitates transmembrane diffusion of small, polar solutes. A constriction within the pore, the aromatic/arginine (ar/R) selectivity filter, is thought to control solute permeability: previous studies on single representative water channel proteins suggest narrow channels conduct water, whilst wider channels permit passage of solutes. To assess this model of selectivity, we used mutagenesis, permeability measurements and in silico comparisons of water-specific as well as glycerol-permeable human AQPs. Our studies show that single amino acid substitutions in the selectivity filters of AQP1, AQP4 and AQP3 differentially affect glycerol and urea permeability in an AQP-specific manner. Comparison between in silico-calculated channel cross-sectional areas and in vitro permeability measurements suggests that selectivity filter cross-sectional area predicts urea but not glycerol permeability. Our data show that substrate discrimination in water channels depends on a complex interplay between the solute, pore size, and polarity, and that using single water channel proteins as representative models has led to an underestimation of this complexity.</p>}},
author = {{Kitchen, Philip and Salman, Mootaz M. and Pickel, Simone U. and Jennings, Jordan and Törnroth-Horsefield, Susanna and Conner, Matthew T. and Bill, Roslyn M. and Conner, Alex C.}},
issn = {{2045-2322}},
language = {{eng}},
number = {{1}},
publisher = {{Nature Publishing Group}},
series = {{Scientific Reports}},
title = {{Water channel pore size determines exclusion properties but not solute selectivity}},
url = {{http://dx.doi.org/10.1038/s41598-019-56814-z}},
doi = {{10.1038/s41598-019-56814-z}},
volume = {{9}},
year = {{2019}},
}