Unsymmetric three component lipid bilayers containing 1 2 dimyristoyl-sn-glycero-3-phosphatidylcho line (DMPC) cholesterol and a ganglioside were prepared using the Langmuir-Blodgett-Langmuir-Schaefer (LB-LS) technique on the surface of a polycrystalline gold electrode The lipid layer contains the ganglioside only in the outer layer mimicking a natural cell membrane Gangliosides are glycolipids containing at least one stalic acid residue and are proposed to be a binding partner for siglec proteins Interaction between Siglec-4 the myelin-associated glycoprotein (MAG) and two gangliosides in lipid bilayers was investigated MAG protein binds only to the sialic acid residue located at the terminal position in the oligosaccharide head group of a lipid molecule In this study two gangliosides the GD(1a), having one terminal sialic acid residue and the GM, not possessing a terminal sialic acid residue in the polar head group were used Under physiological conditions a lipid membrane is constantly exposed to high electric fields Three component lipid Mayers transferred by the LB-LS method are characterized by capacitance minimum equal to 23 and 50 mu F cm(-2) in the film containing the GM, and GD(1a) respectively The lipid bilayer desorbs form the electrode surface at E < -08 V vs Ag vertical bar AgCl The potential driven adsorption-desorption process is irreversible and leads to an Increase in the capacitance of the adsorbed lipid films The lipid films undergo some irreversible changes which may lead to a flip-flop of bilayer fragments formation of micelles on the electrode surface or decrease in surface coverage Exposure of the bilayer to the protein solution stabilizes lipid films adsorbed directly on the electrode surface The potential induced adsorption of the bilayer containing the GD(1a) in the presence of the protein hinders structural changes taking place in the lipid film exposed to changing electric fields At the molecular level the binding of the protein to the GD(1a) introduces structural changes not only in the glycolipid molecule but in the whole membrane In the polar head group of the GD(1a) amide groups in static acid residues lose some water of hydration upon interaction with the protein The hydrocarbon chains of the GD(1a) exhibit ordering with respect to the surface normal Reorientations in the ganglioside molecule may lead to changes in the phosphatidylcholine main lipid component of the bilayer In the DMPC molecule the dehydration of the ester group with simultaneous change in tilt of the acyl chains were observed (C) 2010 Elsevier B V All rights reserved