Physicochemical Study of Several Peptide Constructs Based on the Sequence (96–107) of VP2-HAV Protein

Abstract

A peptide with the amino acid sequence of 96–107 of Hepatitis A virus capsid protein VP2 was synthesized as such (FR2), as stearoyl derivative (stearoyl-FR2), and as a multiple antigen derivative (MAP- FR2) by standard solid phase procedures. The products were characterized by HPLC, mass spectrometry, and amino acid analysis. Their surface properties were studied using Langmuir films. Free peptide as well as its derivatives showed a high surface activity giving surface pressure increases in a concentration dependent way. FR2 molecules reached the air/water interface within few minutes. In contrast, stearoyl-FR2 and MAP4-FR2 showed an induction time concentration dependence, suggesting the presence of aggregates. These products were also able to insert into dipalmitoyl phosphatidyl choline (DPPC), dipalmitoyl phosphatidyl ethanolamine (DPPE) and dipalmitoyl phosphatidyl glycerol (DPPG) monolayers spread at 5, 10, and 20 mN m−1. Miscibility studies of the peptides with phospholipids showed no deviation with respect to ideality, which suggests the presence of weak molecular interactions. Finally, FR2 was incorporated into liposomes in order to study the immunogeneicity and surface activity of these vesicles.