Interaction of lipidated GBV-C/HGV NS3 (513–522) and (505–514) peptides with phospholipids monolayer. An AFM study

Lipidation of a short hydrophilic peptide has the aim to make the molecule amphiphilic, which improves its insertion into lipid monolayer and at the same time, the tendency to self-assembly. These both properties of two positively charged, hepatitis G (GBV-C/HGV) related lipidated peptides—palmitic acid derivatives of the fragments: 505–514 and the 513–522 of the NS3 protein (respectively Palmitoyl-SAELSMQRRG and Palmitoyl-RGRTGRGRSG) were studied. First, using transmission electron microscope (TEM) and atomic force microscope (AFM) the tendency to self-assembly in water solution was examined. Both techniques confirmed the formation of fibrous aggregates of Palmitoyl-SAELSMQRRG in water solution. At the same conditions, any fibrous aggregates of Palmitoyl-RGRTGRGRSG were detected neither by TEM nor by AFM.Insertion of the lipidated peptides into phospholipids monolayer formed by zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or negatively charged 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG) was investigated. Monolayers prepared by Langmuir–Blodgett method were visualized by AFM. The presence of lipidated peptides in phospholipid monolayers produced changes in the monolayers and different morphologies of the monolayers were obtained for each of the lipidated peptides.