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A combined computational and functional approach identifies new residues involved in pH-dependent gating of ASIC1a

Liechti, L. A. and Bernèche, S. and Bargeton, B. and Iwaszkiewicz, J. and Roy, S. and Michielin, O. and Kellenberger, S.. (2010) A combined computational and functional approach identifies new residues involved in pH-dependent gating of ASIC1a. Journal of biological chemistry, Vol. 285, H. 21. pp. 16315-16329.

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Official URL: http://edoc.unibas.ch/dok/A5842506

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Abstract

Acid-sensing ion channels (ASICs) are key receptors for extracellular protons. These neuronal non-voltage-gated Na(+) channels are involved in learning, the expression of fear, neurodegeneration after ischemia, and pain sensation. We have applied a systematic approach to identify potential pH sensors in ASIC1a and to elucidate the mechanisms by which pH variations govern ASIC gating. We first calculated the pKa of all extracellular His, Glu and Asp residues using a Poisson-Boltzmann continuum approach based on the ASIC 3D structure, to identify candidate pH-sensing residues. The role of these residues was then assessed by site-directed mutagenesis and chemical modification, combined with functional analysis. The localization of putative pH-sensing residues suggests that pH changes control ASIC gating by protonation / deprotonation of many residues per subunit in different channel domains. Analysis of the function of residues in the palm domain close to the central vertical axis of the channel allowed for prediction of conformational changes of this region during gating. Our study provides a basis for the intrinsic ASIC pH dependence and describes an approach than can also be applied to the investigation of the mechanisms of the pH dependence of other proteins.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Computational Biophysics (Bernèche)
UniBasel Contributors:Bernèche, Simon
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:American Society of Biological Chemists
ISSN:0021-9258
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:08 Jun 2012 06:56
Deposited On:08 Jun 2012 06:49

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