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Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated cha...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504973/ https://www.ncbi.nlm.nih.gov/pubmed/34590583 http://dx.doi.org/10.7554/eLife.60682 |
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author | Lefebvre, Solène N Taly, Antoine Menny, Anaïs Medjebeur, Karima Corringer, Pierre-Jean |
author_facet | Lefebvre, Solène N Taly, Antoine Menny, Anaïs Medjebeur, Karima Corringer, Pierre-Jean |
author_sort | Lefebvre, Solène N |
collection | PubMed |
description | Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated channel GLIC, we generated several fluorescent sensors of the protein conformation that report a fast transition to a pre-active state, which precedes the slower process of activation with pore opening. Here, we explored the phenotype of a series of allosteric mutations, using simultaneous steady-state fluorescence and electrophysiological measurements over a broad pH range. Our data, fitted to a three-state Monod-Wyman-Changeux model, show that mutations at the subunit interface in the extracellular domain (ECD) principally alter pre-activation, while mutations in the lower ECD and in the transmembrane domain principally alter activation. We also show that propofol alters both transitions. Data are discussed in the framework of transition pathways generated by normal mode analysis (iModFit). It further supports that pre-activation involves major quaternary compaction of the ECD, and suggests that activation involves principally a reorganization of a ‘central gating region’ involving a contraction of the ECD β-sandwich and the tilt of the channel lining M2 helix. |
format | Online Article Text |
id | pubmed-8504973 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-85049732021-10-13 Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation Lefebvre, Solène N Taly, Antoine Menny, Anaïs Medjebeur, Karima Corringer, Pierre-Jean eLife Neuroscience Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated channel GLIC, we generated several fluorescent sensors of the protein conformation that report a fast transition to a pre-active state, which precedes the slower process of activation with pore opening. Here, we explored the phenotype of a series of allosteric mutations, using simultaneous steady-state fluorescence and electrophysiological measurements over a broad pH range. Our data, fitted to a three-state Monod-Wyman-Changeux model, show that mutations at the subunit interface in the extracellular domain (ECD) principally alter pre-activation, while mutations in the lower ECD and in the transmembrane domain principally alter activation. We also show that propofol alters both transitions. Data are discussed in the framework of transition pathways generated by normal mode analysis (iModFit). It further supports that pre-activation involves major quaternary compaction of the ECD, and suggests that activation involves principally a reorganization of a ‘central gating region’ involving a contraction of the ECD β-sandwich and the tilt of the channel lining M2 helix. eLife Sciences Publications, Ltd 2021-09-30 /pmc/articles/PMC8504973/ /pubmed/34590583 http://dx.doi.org/10.7554/eLife.60682 Text en © 2021, Lefebvre et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited. |
spellingShingle | Neuroscience Lefebvre, Solène N Taly, Antoine Menny, Anaïs Medjebeur, Karima Corringer, Pierre-Jean Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title | Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title_full | Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title_fullStr | Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title_full_unstemmed | Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title_short | Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
title_sort | mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation |
topic | Neuroscience |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504973/ https://www.ncbi.nlm.nih.gov/pubmed/34590583 http://dx.doi.org/10.7554/eLife.60682 |
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