Molecular dynamics simulations of hydrophilic pores in lipid bilayers

Leontiadou, H., Mark, A. E. and Marrink, S. J. (2004) Molecular dynamics simulations of hydrophilic pores in lipid bilayers. Biophysical Journal, 86 4: 2156-2164. doi:10.1016/S0006-3495(04)74275-7


Author Leontiadou, H.
Mark, A. E.
Marrink, S. J.
Title Molecular dynamics simulations of hydrophilic pores in lipid bilayers
Journal name Biophysical Journal   Check publisher's open access policy
ISSN 0006-3495
Publication date 2004-04-01
Year available 2004
Sub-type Article (original research)
DOI 10.1016/S0006-3495(04)74275-7
Volume 86
Issue 4
Start page 2156
End page 2164
Total pages 9
Place of publication Bethesda
Publisher Biophysical Society
Language eng
Abstract Hydrophilic pores are formed in peptide free lipid bilayers under mechanical stress. It has been proposed that the transport of ionic species across such membranes is largely determined by the existence of such meta-stable hydrophilic pores. To study the properties of these structures and understand the mechanism by which pore expansion leads to membrane rupture, a series of molecular dynamics simulations of a dipalmitoylphosphatidylcholine (DPPC) bilayer have been conducted. The system was simulated in two different states; first, as a bilayer containing a meta-stable pore and second, as an equilibrated bilayer without a pore. Surface tension in both cases was applied to study the formation and stability of hydrophilic pores inside the bilayers. It is observed that below a critical threshold tension of similar to38 mN/m the pores are stabilized. The minimum radius at which a pore can be stabilized is 0.7 nm. Based on the critical threshold tension the line tension of the bilayer was estimated to be similar to3x10(-11) N, in good agreement with experimental measurements. The flux of water molecules through these stabilized pores was analyzed, and the structure and size of the pores characterized. When the lateral pressure exceeds the threshold tension, the pores become unstable and start to expand causing the rupture of the membrane. In the simulations the mechanical threshold tension necessary to cause rupture of the membrane on a nanosecond timescale is much higher in the case of the equilibrated bilayers, as compared with membranes containing preexisting pores.
Keyword Biophysics
Reversible Electrical Breakdown
Membranes
Permeability
Water
Electroporation
Phospholipids
Permeation
Vesicles
Channel
Rupture
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemistry and Molecular Biosciences
 
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Created: Thu, 20 Sep 2007, 04:55:44 EST