Membrane binding and conformational properties of peptides representing the NH2 terminus of influenza HA-2

Synthetic peptides representing amino acid residues 1-16 and 1-20, a proposed fusogenic region of the HA-2 subunit of influenza virus hemagglutinin, bind to phosphatidylcholine vesicles with submicromolar dissociation constants. The 1-20, but not the 1-16, peptide appears to adopt a helical conformation when bound to vesicles and cooperatively promotes vesicle fusion.