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Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation
The chemotaxis system in the bacterium Escherichia coli is remarkably sensitive to small relative changes in the concentrations of multiple chemical signals over a broad range of ambient concentrations. Interactions among receptors are crucial to this sensitivity as is precise adaptation, the return...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2008
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174977/ https://www.ncbi.nlm.nih.gov/pubmed/18179279 http://dx.doi.org/10.1371/journal.pcbi.0040001 |
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author | Hansen, Clinton H Endres, Robert G Wingreen, Ned S |
author_facet | Hansen, Clinton H Endres, Robert G Wingreen, Ned S |
author_sort | Hansen, Clinton H |
collection | PubMed |
description | The chemotaxis system in the bacterium Escherichia coli is remarkably sensitive to small relative changes in the concentrations of multiple chemical signals over a broad range of ambient concentrations. Interactions among receptors are crucial to this sensitivity as is precise adaptation, the return of chemoreceptor activity to prestimulus levels in a constant chemoeffector environment. Precise adaptation relies on methylation and demethylation of chemoreceptors by the enzymes CheR and CheB, respectively. Experiments indicate that when transiently bound to one receptor, these enzymes act on small assistance neighborhoods (AN) of five to seven receptor homodimers. In this paper, we model a strongly coupled complex of receptors including dynamic CheR and CheB acting on ANs. The model yields sensitive response and precise adaptation over several orders of magnitude of attractant concentrations and accounts for different responses to aspartate and serine. Within the model, we explore how the precision of adaptation is limited by small AN size as well as by CheR and CheB kinetics (including dwell times, saturation, and kinetic differences among modification sites) and how these kinetics contribute to noise in complex activity. The robustness of our dynamic model for precise adaptation is demonstrated by randomly varying biochemical parameters. |
format | Text |
id | pubmed-2174977 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2008 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-21749772008-01-05 Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation Hansen, Clinton H Endres, Robert G Wingreen, Ned S PLoS Comput Biol Research Article The chemotaxis system in the bacterium Escherichia coli is remarkably sensitive to small relative changes in the concentrations of multiple chemical signals over a broad range of ambient concentrations. Interactions among receptors are crucial to this sensitivity as is precise adaptation, the return of chemoreceptor activity to prestimulus levels in a constant chemoeffector environment. Precise adaptation relies on methylation and demethylation of chemoreceptors by the enzymes CheR and CheB, respectively. Experiments indicate that when transiently bound to one receptor, these enzymes act on small assistance neighborhoods (AN) of five to seven receptor homodimers. In this paper, we model a strongly coupled complex of receptors including dynamic CheR and CheB acting on ANs. The model yields sensitive response and precise adaptation over several orders of magnitude of attractant concentrations and accounts for different responses to aspartate and serine. Within the model, we explore how the precision of adaptation is limited by small AN size as well as by CheR and CheB kinetics (including dwell times, saturation, and kinetic differences among modification sites) and how these kinetics contribute to noise in complex activity. The robustness of our dynamic model for precise adaptation is demonstrated by randomly varying biochemical parameters. Public Library of Science 2008-01 2008-01-04 /pmc/articles/PMC2174977/ /pubmed/18179279 http://dx.doi.org/10.1371/journal.pcbi.0040001 Text en © 2008 Hansen 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 Hansen, Clinton H Endres, Robert G Wingreen, Ned S Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title | Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title_full | Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title_fullStr | Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title_full_unstemmed | Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title_short | Chemotaxis in Escherichia coli: A Molecular Model for Robust Precise Adaptation |
title_sort | chemotaxis in escherichia coli: a molecular model for robust precise adaptation |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174977/ https://www.ncbi.nlm.nih.gov/pubmed/18179279 http://dx.doi.org/10.1371/journal.pcbi.0040001 |
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