A molecular theory for nonohmicity of the ion leak across the lipid- bilayer membrane

Youhei Fujitani, Dick Bedeaux

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The current-voltage relationship of ion leak (i.e., ion transport involving neither special channels nor carriers) across the lipid-bilayer membrane has been observed to be log-linear above the ohmic regime. The coefficient of the linear term has been found to be universal for membranes and penetrants examined. This universality has been explained in terms of diffusion in an external field, where the ion position is described as a Markovian process. Such a diffusion picture can be questioned, however. It is also probable that a leaking ion gets over the potential barrier before experiencing sufficient random collision in the membrane, considering that each ion is surrounded with long lipid molecules aligned almost unidirectional y. As an alternative, we discuss this ion leak in terms of velocity distribution of the ions entering the membrane and density fluctuation of the lipids. We conclude that we can explain the universality without resorting to the diffusion picture.

Original languageEnglish
Pages (from-to)1805-1814
Number of pages10
JournalBiophysical Journal
Volume73
Issue number4
DOIs
Publication statusPublished - 1997 Oct

ASJC Scopus subject areas

  • Biophysics

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