PHYSICOCHEMICAL STUDY OF SEVERAL PEPTIDE CONSTRUCTS BASED ON THE SEQUENCE (96-107) OF VP2-HAV PROTEIN

A peptide with the amino acid sequence of 96-107 of Hepatitis A virus capsid protein VP2 was synthesized as such (FR2), as stearoyl derivati ve (stearoyl-FR2), and as a multiple antigen derivative (MAP- FR2) by standard solid phase procedures. The products were characterized by HP LC, mass spectrometry, and amino acid analysis. Their surface properti es were studied using Langmuir films. Free peptide as well as its deri vatives showed a high surface activity giving surface pressure increas es in a concentration dependent way. FR2 molecules reached the air/wat er interface within few minutes. In contrast, stearoyl-FR2 and MAP(4)- FR2 showed an induction time concentration dependence, suggesting the presence of aggregates. These products were also able to insert into d ipalmitoyl phosphatidyl choline (DPPC), dipalmitoyl phosphatidyl ethan olamine (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, whic h suggests the presence of weak molecular interactions. Finally, FR2 w as incorporated into liposomes in order to study the immunogeneicity a nd surface activity of these vesicles. (C) 1997 Academic Press.