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Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B
Urea transporter B (UT-B) is a passive membrane channel that facilitates highly efficient permeation of urea. In red blood cells (RBC), while the major function of UT-B is to transport urea, it is assumed that this protein is able to conduct water. Here, we have revisited this last issue by studying...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869693/ https://www.ncbi.nlm.nih.gov/pubmed/24376529 http://dx.doi.org/10.1371/journal.pone.0082338 |
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author | Azouzi, Slim Gueroult, Marc Ripoche, Pierre Genetet, Sandrine Colin Aronovicz, Yves Le Van Kim, Caroline Etchebest, Catherine Mouro-Chanteloup, Isabelle |
author_facet | Azouzi, Slim Gueroult, Marc Ripoche, Pierre Genetet, Sandrine Colin Aronovicz, Yves Le Van Kim, Caroline Etchebest, Catherine Mouro-Chanteloup, Isabelle |
author_sort | Azouzi, Slim |
collection | PubMed |
description | Urea transporter B (UT-B) is a passive membrane channel that facilitates highly efficient permeation of urea. In red blood cells (RBC), while the major function of UT-B is to transport urea, it is assumed that this protein is able to conduct water. Here, we have revisited this last issue by studying RBCs and ghosts from human variants with defects of aquaporin 1 (AQP1) or UT-B. We found that UT-B's osmotic water unit permeability (pf(unit)) is similar to that of AQP1. The determination of diffusional permeability coefficient (P(d)) allowed the calculation of the P(f)/P(d) ratio, which is consistent with a single-file water transport. Molecular dynamic simulations of water conduction through human UT-B confirmed the experimental finding. From these results, we propose an atomistic description of water–protein interactions involved in this permeation. Inside the UT-B pore, five water molecules were found to form a single-file and move rapidly along a channel by hydrogen bond exchange involving two critical threonines. We further show that the energy barrier for water located in the central region coincides with a water dipole reorientation, which can be related to the proton exclusion observed experimentally. In conclusion, our results indicate that UT-B should be considered as a new member of the water channel family. |
format | Online Article Text |
id | pubmed-3869693 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-38696932013-12-27 Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B Azouzi, Slim Gueroult, Marc Ripoche, Pierre Genetet, Sandrine Colin Aronovicz, Yves Le Van Kim, Caroline Etchebest, Catherine Mouro-Chanteloup, Isabelle PLoS One Research Article Urea transporter B (UT-B) is a passive membrane channel that facilitates highly efficient permeation of urea. In red blood cells (RBC), while the major function of UT-B is to transport urea, it is assumed that this protein is able to conduct water. Here, we have revisited this last issue by studying RBCs and ghosts from human variants with defects of aquaporin 1 (AQP1) or UT-B. We found that UT-B's osmotic water unit permeability (pf(unit)) is similar to that of AQP1. The determination of diffusional permeability coefficient (P(d)) allowed the calculation of the P(f)/P(d) ratio, which is consistent with a single-file water transport. Molecular dynamic simulations of water conduction through human UT-B confirmed the experimental finding. From these results, we propose an atomistic description of water–protein interactions involved in this permeation. Inside the UT-B pore, five water molecules were found to form a single-file and move rapidly along a channel by hydrogen bond exchange involving two critical threonines. We further show that the energy barrier for water located in the central region coincides with a water dipole reorientation, which can be related to the proton exclusion observed experimentally. In conclusion, our results indicate that UT-B should be considered as a new member of the water channel family. Public Library of Science 2013-12-20 /pmc/articles/PMC3869693/ /pubmed/24376529 http://dx.doi.org/10.1371/journal.pone.0082338 Text en © 2013 Azouzi et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Azouzi, Slim Gueroult, Marc Ripoche, Pierre Genetet, Sandrine Colin Aronovicz, Yves Le Van Kim, Caroline Etchebest, Catherine Mouro-Chanteloup, Isabelle Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title | Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title_full | Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title_fullStr | Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title_full_unstemmed | Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title_short | Energetic and Molecular Water Permeation Mechanisms of the Human Red Blood Cell Urea Transporter B |
title_sort | energetic and molecular water permeation mechanisms of the human red blood cell urea transporter b |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869693/ https://www.ncbi.nlm.nih.gov/pubmed/24376529 http://dx.doi.org/10.1371/journal.pone.0082338 |
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