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Molecular Dynamics Simulations of Ion Permeation in Human Voltage-Gated Sodium Channels
Journal article   Open access   Peer reviewed

Molecular Dynamics Simulations of Ion Permeation in Human Voltage-Gated Sodium Channels

Giulio Alberini, Sergio Alexis Paz, Beatrice Corradi, Cameron F Abrams, Fabio Benfenati and Luca Maragliano
Journal of chemical theory and computation
28 Apr 2023
DOI: https://doi.org/10.1021/acs.jctc.2c00990
PMID: 37116214
Featured in Collection :   UN Sustainable Development Goals @ Drexel
url
https://doi.org/10.1021/acs.jctc.2c00990View
Published, Version of Record (VoR)CC BY V4.0,  Open

Abstract

The recent determination of cryo-EM structures of voltage-gated sodium (Na-v) channels has revealed many details of these proteins. However, knowledge of ionic permeation through the Na-v pore remains limited. In this work, we performed atomistic molecular dynamics (MD) simulations to study the structural features of various neuronal Na-v channels based on homology modeling of the cryo-EM structure of the human Na 1.4 channel and, in addition, on the recently resolved configuration for Na v 1.2. In particular, single Na-v permeation events during standard MD runs suggest that the ion resides in the inner part of the Na-v selectivity filter (SF). On-the-fly free energy parametrization (OTFP) temperature-accelerated molecular dynamics (TAMD) was also used to calculate two-dimensional free energy surfaces (FESs) related to single/double Na-v translocation through the SF of the homology-based Na-v 1.2 model and the cryo-EM Na-v 1.2 structure, with different realizations of the DEKA filter domain. These additional simulations revealed distinct mechanisms for single and double Na-v permeation through the wild-type SF, which has a charged lysine in the DEKA ring. Moreover, the configurations of the ions in the SF corresponding to the metastable states of the FESs are specific for each SF motif. Overall, the description of these mechanisms gives us new insights into ion conduction in human Na-v cryo-EM-based and cryo-EM configurations that could advance understanding of these systems and how they differ from potassium and bacterial Na-v channels.

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14 citations in Web of Science
11 citations in Scopus

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Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
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