STRUCTURAL AND FUNCTIONAL SIMILARITIES BETWEEN SYNTHETIC HIV GP41 PEPTIDES AND DEFENSINS

Synthetic peptides derived from the putative immunosuppressive region of HIV-1 gp41 were examined to identify the amino acids required for s uppressive activity. The active sequence was similar to the pseudosubs trate regulatory peptide of protein kinase C and to a sequence from th e cyclic immune peptides known as defensins. The activity of the gp41 peptides appeared to be dependent upon a structural conformation, poss ibly a looped motif like that found in defensins. This similarity to d efensins, which can insert themselves into lipid bilayers, was further strengthened by demonstrating that gp41 peptides have the ability to associate with liposomes and lymphocyte membranes. These results sugge st that the immunosuppressive region of gp41 may participate in the me mbrane interactions required for viral fusion and infectivity. (C) 199 4 Academic Press, Inc.