Ion transport across transmembrane pores

Leontiadou, H, Mark, AE and Marrink, SJ (2007) Ion transport across transmembrane pores. Biophysical Journal, 92 12: 4209-4215. doi:10.1529/biophysj.106.101295


Author Leontiadou, H
Mark, AE
Marrink, SJ
Title Ion transport across transmembrane pores
Journal name Biophysical Journal   Check publisher's open access policy
ISSN 0006-3495
Publication date 2007-06-01
Sub-type Article (original research)
DOI 10.1529/biophysj.106.101295
Volume 92
Issue 12
Start page 4209
End page 4215
Total pages 7
Place of publication Bethesda
Publisher Biophysical Society
Collection year 2008
Language eng
Subject C1
780103 Chemical sciences
Abstract To study the pore-mediated transport of ionic species across a lipid membrane, a series of molecular dynamics simulations have been performed of a dipalmitoyl-phosphatidyl-choline bilayer containing a preformed water pore in the presence of sodium and chloride ions. It is found that the stability of the transient water pores is greatly reduced in the presence of the ions. Specifically, the binding of sodium cations at the lipid/water interface increases the pore line tension, resulting in a destabilization of the pore. However, the application of mechanical stress opposes this effect. The flux of ions through these mechanically stabilized pores has been analyzed. Simulations indicate that the transport of the ions through the pores depends strongly on the size of the water channel. In the presence of small pores (radius <1.5 nm) permeation is slow, with both sodium and chloride permeating at similar rates. In the case in which the pores are larger (radius <1.5 nm), a crossover is observed to a regime where the anion flux is greatly enhanced. Based on these observations, a mechanism for the basal membrane permeability of ions is discussed.
Keyword Biophysics
Molecular-dynamics Simulations
Lipid-bilayers
Phospholipid-bilayers
Free-energy
Transient Pores
Giant Vesicles
Line Tension
Membranes
Permeation
Water
Q-Index Code C1
Q-Index Status Confirmed Code

 
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Created: Tue, 19 Feb 2008, 03:20:16 EST