Interaction of three beta-interferon domains with liposomes and monolayers as model membranes

The physicochemical properties of three peptides belonging to the beta-interferon (beta-IFN) molecule, -beta-IFN(13-20), beta-IFN(40-47) and beta-IFN(109-116)-, which have been described to be antigenic epitopes of the neutralising antibodies responsible of the failure of the Multiple Sclerosis therapy, and their palmitoylated derivatives were analysed. Peptides were synthesised by solid-phase methodologies and characterized by amino acid analysis, analytical high-performance liquid chromatography and electrospray mass spectrometry. The activity of free and derivatized peptides was determined. In order to know how the synthesised peptides were able to interact with membrane models, studies of kinetics of penetration at constant area and compression isotherms were carried out. Moreover, differential scanning calorimetry (DSC) was used to investigate the thermotropic phase properties of binary mixtures of dipalmitoylphosphatidylcholine (DPPC) or dipalmitoylphosphatidylglicerol (DPPG) with the peptides.