Miscibility of hepatitis A synthetic antigen peptides with lipid monolayers: Effect of the amino acid sequence change

Interaction of hepatitis A virus (HAV) with cells during infection and immunological response is not yet well-known. It seems that hydrophobic and electrostatic interactions with the membrane lipids play an important role as well as the RGD triplet located within the (110-121) linear HAV epitope which belongs to the HAV-VP3 structural protein. To obtain more knowledge about these interactions in the present work we have studied the miscibility of two HAV peptides (where the RGD triplet was replaced by RGE and RKD) with three different lipids (dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, and stearylamine) through compression isotherms. Both peptides [Lys]¹¹³ VP3110 and [Glu]¹¹⁴ VP3110 showed deviations from ideality consistent with miscibility, except in some cases at the collapse pressure. In all cases the interactions were higher with [Glu]¹¹⁴ VP3110. However, these interactions were positive in the majority of cases and then not related with the net charge of the lipid that was different in any case. These results seems to point to the fact that hydrophobic interactions play a major role, even though the compressibility of the peptide should also to be taken into account.