Electroporation of archaeal lipid membranes using MD simulations

Molecular dynamics (MD) simulations were used to investigate the electroporation of archaeal lipid bilayers when subjected to high transmembrane voltages induced by a charge imbalance, mimicking therefore millisecond electric pulse experiments. The structural characteristics of the bilayer, a 9:91mo...

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Published in:Bioelectrochemistry (Amsterdam, Netherlands) Netherlands), 2014-12, Vol.100, p.18-26
Main Authors: Polak, Andraž, Tarek, Mounir, Tomšič, Matija, Valant, Janez, Ulrih, Nataša Poklar, Jamnik, Andrej, Kramar, Peter, Miklavčič, Damijan
Format: Article
Language:English
Subjects:
Aeropyrum pernix
Archaea - cytology
Charge imbalance
Electric Capacitance
Electroporation
Lipid bilayers
Lipid Bilayers - chemistry
Lipid Bilayers - metabolism
Molecular Conformation
Molecular Dynamics Simulation
Porosity
Scattering, Small Angle
Transmembrane voltage
Unilamellar Liposomes - chemistry
Unilamellar Liposomes - metabolism
X-Ray Diffraction
X-ray scattering
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Summary:Molecular dynamics (MD) simulations were used to investigate the electroporation of archaeal lipid bilayers when subjected to high transmembrane voltages induced by a charge imbalance, mimicking therefore millisecond electric pulse experiments. The structural characteristics of the bilayer, a 9:91mol% 2,3-di-O-sesterterpanyl-sn-glicerol-1-phospho-myo-inositol (AI) and 2,3-di-O-sesterterpanyl-sn-glicerol-1-phospho-1′(2′-O-α-d-glucosyl)-myo-inositol (AGI) were compared to small angle X-ray scattering data. A rather good agreement of the electron density profiles at temperatures of 298 and 343K was found assessing therefore the validity of the protocols and force fields used in simulations. Compared to dipalmitoyl-phosphatidylcholine (DPPC), the electroporation threshold for the bilayer was found to increase from ~2V to 4.3V at 323K, and to 5.2V at 298K. Comparing the electroporation thresholds of the archaeal lipids to those of simple diphytanoyl-phosphatidylcholine (DPhPC) bilayers (2.5V at 323K) allowed one to trace back the stability of the membranes to the structure of their lipid head groups. Addition of DPPC in amounts of 50mol% to the archaeal lipid bilayers decreases their stability and lowers the electroporation thresholds to 3.8V and 4.1V at respectively 323 and 298K. The present study therefore shows how membrane compositions can be selected to cover a wide range of responses to electric stimuli. This provides new routes for the design of liposomes that can be efficiently used as drug delivery carriers, as the selection of their composition allows one to tune in their electroporation threshold for subsequent release of their load. •MD simulations are in good agreement with SAXS results.•The archaeal lipid bilayers have high electroporation threshold.•During electroporation in archaeal lipid bilayers, we observed hydrophobic pores.
ISSN:1567-5394
1878-562X
DOI:10.1016/j.bioelechem.2013.12.006