Poster Presentation 2014 International Biophysics Congress

P { margin-bottom: 0.08in; } Electrostatic component contribution to the energetics of ion permeation through a Na+ channel (#577)

Leticia Stock 1 , Vincenzo Carnevale 2 , Werner Treptow 1 , Michael L, Klein 2
  1. Universidade de Brasilia, Brasilia, DF, Brazil
  2. Temple University, Philadelphia, PA, USA

In the last three years, various voltage-gated sodium channel's (VGSCs) crystal structures have been resolved, the first of them being the Arcobacter butzleri channel called NavAb.1  These structures provide with an opportunity to tackle essential issues concerning the understanding of sodium channel (SC) structure-function interplay, by allowing their study in atomistic scale via computational methodologies. Critical questions, integral to ion channel function, include the ion conduction and selectivity mechanisms. Recent studies have harnessed such structures to shed light on these topics, either by enhanced sampling techniques, either by sampling very long molecular dynamics simulations.23456  In both cases however the computational costs associated with such investigation cannot bet neglected. Additionally, because of the ion's charge and reduced size, it is reasonable to expect the electrostatic component of the potential of mean force (PMF) associated with ion permeation through the channel to be a dominant term. Face of this scenario, the present contribution wishes to investigate the applicability of using continuum electrostatic calculations, via solution of the poisson-boltzmann equation (PB), to draw relevant conclusions about conduction and selectivity in VGSCs. This was done by computing the axial (z axis, perpendicular to the membrane plane) and axial-radial PMF associated with Na+/K+ permeation through NavAb both via metadynamics and PB.

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