Interaction of LL-37 with model membrane systems of different complexity -
Influence of the lipid matrix
Eva Sevcsik 1*, Georg Pabst 1, Walter Richter 2, Sabine Danner 1, Heinz Amenitsch 1 and Karl Lohner 1
1 Austrian Academy of Sciences
2 Friedrich-Schiller-Universität Jena
* To whom correspondence should be addressed. E-mail: eva.sevcsik{at}oeaw.ac.at.
Submitted on October 9, 2007
Revised on November 22, 2007
Accepted on 23 January 2008
 |
Abstract |
|---|
As the main difference between bacterial and mammalian cell membranes is their net charge, the focal point of consideration in many model membrane experiments with antimicrobial peptides is lipid headgroup charge. We studied the interaction of the human multifunctional peptide LL-37 with single phospholipid monolayers, bilayers and bilayers composed of binary mixtures of the four phospholipid species predominantly used in model membrane experiments (phosphatidyl-choline, -ethanolamine, -glycerol and -serine). We found (i) that the effects on single lipid monolayers are not comparable to those on the corresponding bilayers, (ii) four different effects of LL-37 on bilayers of the four lipids, (iii) that the preference of LL-37 for the specific lipids is roughly inversely related to chain packing density and (iv) that in the binary lipid mixtures one lipid generally governs the mode of lipid/peptide interaction, which is not necessarily the charged one. Thus, our results show that lipid net charge is not the decisive factor determining the membrane-perturbing mechanism of LL-37 but only one of several parameters, among them packing density, the ability to form intermolecular H-bonds and lipid molecular shape, emphasizing how profoundly the choice of the model system can influence the outcome of a study of lipid/peptide interaction.
Key Words:
antimicrobial peptide, bilayer, lipid-peptide interaction, membrane mimetics, monolayer, net charge
