help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published March 2, 2006. doi:10.1529/biophysj.105.074666
© 2006 by the Biophysical Society.

A more recent version of this article appeared on June 1, 2006.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.105.074666v1
90/11/4060    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Author home page(s):
Thomas Starke-Peterkovic
Nigel Turner
Mark F Vitha
Mark P Waller
David E Hibbs
Ronald J Clarke
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Starke-Peterkovic, T.
Right arrow Articles by Clarke, R. J
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Starke-Peterkovic, T.
Right arrow Articles by Clarke, R. J

MEMBRANES

Cholesterol Effect on the Dipole Potential of Lipid Membranes

Thomas Starke-Peterkovic 1, Nigel Turner 2, Mark F Vitha 3, Mark P Waller 4, David E Hibbs 4 and Ronald J Clarke 5*

1 Univsersity of Orsay
2 Garvan Institute
3 Drake University
4 University of Sydney
5 The University of Sydney F-11 School of Chemistry

* To whom correspondence should be addressed. E-mail: r.clarke{at}chem.usyd.edu.au.

Submitted on September 16, 2005
Revised on November 3, 2005
Accepted on 18 January 2006


  Abstract
The effect of cholesterol removal by methyl-{beta}-cyclodextrin on the dipole potential, {psi}d, of membrane vesicles composed of natural membrane lipids extracted from the kidney and brain of eight vertebrate species was investigated using the voltage-sensitive fluorescent probe di-8-ANEPPS. Cyclodextrin treatment reduced cholesterol levels by on average 80% and this was associated with an average reduction in {psi}d of 50 mV. Measurements of the effect of a range of cholesterol derivatives on the {psi}d of DMPC lipid vesicles showed that the magnitude of the effect correlated with the component of the sterol's dipole moment perpendicular to the membrane surface. The changes in {psi}d observed could not be accounted for solely by the electric field originating from the sterols' dipole moments. Additional factors must arise from sterol-induced changes in lipid packing, which changes the density of dipoles in the membrane, and changes in water penetration into the membrane, which changes the effective dielectric constant of the interfacial region. In DMPC membranes the cholesterol-induced change in {psi}d was biphasic, i.e. a maximum in {psi}d was observed at ~35-45 mol%, after which {psi}d started to decrease. We suggest that this could be associated with a maximum in the strength of DMPC-cholesterol intermolecular forces at this composition.

Key Words: density functional calculation, fluorescence, lipid vesicles, methyl-beta-cyclodextrin, oxysterols, voltage-sensitive styryl dyes




This article has been cited by other articles:


Home page
 Biophys. JHome page
Y. Zhou and R. M. Raphael
Solution pH Alters Mechanical and Electrical Properties of Phosphatidylcholine Membranes: Relation between Interfacial Electrostatics, Intramembrane Potential, and Bending Elasticity
Biophys. J., April 1, 2007; 92(7): 2451 - 2462.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2006 by the Biophysical Society.