Effect of variation in the chain length and number in modulating the interaction of an immunogenic lipopeptide with biomembrane models

A differential scanning calorimetry study was carried out to investigate the effect exerted by immunogenic synthetic lipopeptides obtained by the conjugation of LCMV33-41 peptide with lipoamino acids (Laas) bearing different alkyl chain lengths (C-12 and C-16) and number of chains (2 x C-12) on the thermotropic behaviour of dimyristoylphosphatidylcholine (DMPC) liposomes. The aim of this work was to study the ability of these compounds to be carried by a liposomal system and released to a biomembrane model. The examined compounds caused variations of the thermotropic parameters that characterise the liposomal system (transition temperature, T-m and enthalpy variation, Delta H), and interacted with the biomembrane models in different way. The interaction was found to be modulated by the length and number of chains present in the examined compounds. In fact, the compounds with higher number of lipid chain showed a stronger interaction with the biomembrane models with respect to the pure peptide and the compounds with a single lipid chain. These results suggest that the lipoamino acid moiety could favour the peptide to be carried by the liposomal system and released to biomembrane. (C) 2008 Elsevier B.V. All rights reserved.