Effects of cholesterol on dry bilayers: interactions between phosphatidylcholine unsaturation, and glycolipid or free sugar
Antoaneta V Popova 1 and Dirk K Hincha 2*
1 Institute of Biophysics
2 MPI of Molecular Plant Physiology
* To whom correspondence should be addressed. E-mail: hincha{at}mpimp-golm.mpg.de.
Submitted on March 14, 2007
Revised on April 17, 2007
Accepted on 24 April 2007
 |
Abstract |
|---|
Cholesterol and other sterols are important components of biological membranes and are known to strongly influence the physical characteristics of lipid bilayers. While this has been studied extensively in fully hydrated membranes, only little is known about the effects of cholesterol on the stability of membranes in the dry state. Here, we present a Fourier-transform infrared spectroscopy (FTIR) study on the effects of cholesterol on the phase behavior of dry liposomes composed of phosphatidylcholines with different degrees of fatty acid unsaturation, or of mixtures of phosphatidylcholine with a plant galactolipid. In addition, we have analyzed the H-bonding of cholesterol, galactose, and a combination of the two additives to the P=O and C=O groups in dry phosphatidylcholine bilayers. The data indicate a complex balance of interactions between the different components in the dry state and a strong influence of fatty acid unsaturation on the interactions of the diacyl lipids with both cholesterol and galactose.
Key Words:
desiccation, glycolipid, membranes, phase transition, phospholipid, sterol
