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    Molecular dynamics of ion transport through the open conformation of a bacterial voltage-gated sodium channel

    Ulmschneider, Martin B. and Bagneris, Claire and McCusker, Emily C. and DeCaen, P.G. and Delling, M. and Clapham, D.E. and Ulmschneider, J.P. and Wallace, Bonnie A. (2013) Molecular dynamics of ion transport through the open conformation of a bacterial voltage-gated sodium channel. Proceedings of the National Academy of Sciences of the United States of America 110 (16), pp. 6364-6369. ISSN 0027-8424.

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    Abstract

    The crystal structure of the open conformation of a bacterial voltage-gated sodium channel pore from Magnetococcus sp. (NaVMs) has provided the basis for a molecular dynamics study defining the channel’s full ion translocation pathway and conductance process, selectivity, electrophysiological characteristics, and ion-binding sites. Microsecond molecular dynamics simulations permitted a complete time-course characterization of the protein in a membrane system, capturing the plethora of conductance events and revealing a complex mixture of single and multi-ion phenomena with decoupled rapid bidirectional water transport. The simulations suggest specific localization sites for the sodium ions, which correspond with experimentally determined electron density found in the selectivity filter of the crystal structure. These studies have also allowed us to identify the ion conductance mechanism and its relation to water movement for the NavMs channel pore and to make realistic predictions of its conductance properties. The calculated single-channel conductance and selectivity ratio correspond closely with the electrophysiology measurements of the NavMs channel expressed in HEK 293 cells. The ion translocation process seen in this voltage-gated sodium channel is clearly different from that exhibited by members of the closely related family of voltage-gated potassium channels and also differs considerably from existing proposals for the conductance process in sodium channels. These studies simulate sodium channel conductance based on an experimentally determined structure of a sodium channel pore that has a completely open transmembrane pathway and activation gate.

    Metadata

    Item Type: Article
    School: Birkbeck Schools and Departments > School of Science > Biological Sciences
    Research Centre: Bioinformatics, Bloomsbury Centre for, Structural Molecular Biology, Institute of (ISMB)
    Depositing User: Administrator
    Date Deposited: 08 Apr 2013 08:56
    Last Modified: 29 Jul 2019 08:27
    URI: http://eprints.bbk.ac.uk/id/eprint/6414

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