Study in mono and bilayers of the interaction of hepatitis G virus (GBV-C/HGV) synthetic antigen E2(99-118) with cell membrane phospholipids

The interaction of the hepatitis G synthetic peptide E2(99-118) with cell membrane phospholipids of different characteristics such as dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) was studied by Langmuir isotherms. Epifluorescence microscopy and Atomic force microscopy (AFM) was also used to study interactions with DPPC. Compression isotherms of DPPC/E2(99-118) and DPPG/E2(99-118) mixed monolayers showed negative deviation from ideallity consistent with the existence of attractive interactions. The incorporation of the peptide in DPPC monolayer was also confirmed in epifluorescence microscopy and AFM studies. The peptide retarded the formation of DPPC domains and did not let the phospholipid get organized. No important differences in the interactions with DPPC (neutral) or DPPG (anionic) were found, thus suggesting that electrostatics forces do not have a predominant influence in these interactions.