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Simplified bacterial “pore” channel provides insight into the assembly, stability and structure of sodium channels

McCusker, Emily C. and d'Avanzo, N. and Nichols, C.G. and Wallace, Bonnie A. (2011) Simplified bacterial “pore” channel provides insight into the assembly, stability and structure of sodium channels. Journal of Biological Chemistry 286 (18), pp. 16386-16391. ISSN 0021-9258.

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Official URL: http://dx.doi.org/10.1074/jbc.C111.228122

Abstract

Eukaryotic sodium channels are important membrane proteins involved in ion permeation, homeostasis, and electrical signaling. They are long, multidomain proteins that do not express well in heterologous systems, and hence, structure/function and biochemical studies on purified sodium channel proteins have been limited. Bacteria produce smaller, homologous tetrameric single domain channels specific for the conductance of sodium ions. They consist of N-terminal voltage sensor and C-terminal pore subdomains. We designed a functional pore-only channel consisting of the final two transmembrane helices, the intervening P-region, and the C-terminal extramembranous region of the sodium channel from the marine bacterium Silicibacter pomeroyi. This sodium “pore” channel forms a tetrameric, folded structure that is capable of supporting sodium flux in phospholipid vesicles. The pore-only channel is more thermally stable than its full-length counterpart, suggesting that the voltage sensor subdomain may destabilize the full-length channel. The pore subdomains can assemble, fold, and function independently from the voltage sensor and exhibit similar ligand-blocking characteristics as the intact channel. The availability of this simple pore-only construct should enable high-level expression for the testing of potential new ligands and enhance our understanding of the structural features that govern sodium selectivity and permeability.

Item Type: Article
Additional Information: This research was originally published in The Journal of Biological Chemistry. Emily C. McCusker, Nazzareno D'Avanzo, Colin G. Nichols and B. A. Wallace. Simplified Bacterial “Pore” Channel Provides Insight into the Assembly, Stability, and Structure of Sodium Channels. The Journal of Biological Chemistry. 2011; 286(18):16386-16391. © The American Society for Biochemistry and Molecular Biology License information: http://creativecommons.org/licenses/by-nc/3.0/
Keyword(s) / Subject(s): circular dichroism (cd), membrane proteins, protein stability, protein structure, sodium channels, protein design, quaternary structure, structure/function relationship
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Biological Sciences
Depositing User: Sarah Hall
Date Deposited: 22 Jun 2012 07:13
Last Modified: 17 Apr 2013 12:23
URI: http://eprints.bbk.ac.uk/id/eprint/4752

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