Referenced in: none

Automatically associated channels: Slo1

Title: Current and selectivity in a model sodium channel under physiological conditions: Dynamic Monte Carlo simulations.

Authors: Eva Csányi, Dezso Boda, Dirk Gillespie, Tamás Kristóf

Journal, date & volume: Biochim. Biophys. Acta, 2012 Mar , 1818, 592-600

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22080102

Abstract
A reduced model of a sodium channel is analyzed using Dynamic Monte Carlo simulations. These include the first simulations of ionic current under approximately physiological ionic conditions through a model sodium channel and an analysis of how mutations of the sodium channel's DEKA selectivity filter motif transform the channel from being Na(+) selective to being Ca(2+) selective. Even though the model of the pore, amino acids, and permeant ions is simplified, the model reproduces the fundamental properties of a sodium channel (e.g., 10 to 1 Na(+) over K(+) selectivity, Ca(2+) exclusion, and Ca(2+) selectivity after several point mutations). In this model pore, ions move through the pore one at a time by simple diffusion and Na(+) versus K(+) selectivity is due to both the larger K(+) not fitting well into the selectivity filter that contains amino acid terminal groups and K(+) moving more slowly (compared to Na(+)) when it is in the selectivity filter.