R. Ishiguro et al., INTERACTION OF FUSOGENIC SYNTHETIC PEPTIDE WITH PHOSPHOLIPID-BILAYERS- ORIENTATION OF THE PEPTIDE ALPHA-HELIX AND BINDING ISOTHERM, Biochemistry, 35(15), 1996, pp. 4976-4983
We studied the binding characteristics of a synthetic 20-residue pepti
de to supported single planar bilayers of phosphatidylcholine, and the
orientation of the peptide by Fourier-transform infrared spectroscopy
with an attenuated total reflection method. This peptide, designed to
resemble a putative fusion peptide of influenza virus hemagglutinin,
assumes an amphiphilic alpha-helix and induces fusion of Liposomes in
an acidic solution (pH similar to 5). At neutral pH, the peptides were
bound to lipid bilayers in the manner of a Langmuir's adsorption isot
herm, and their orientation was nearly random or oblique. On the other
hand, at acidic pH, the peptides were bound, making their helix axis
parallel to the membrane surface, and the binding was cooperative. Thi
s cooperativity suggested dimerization of the peptides. These characte
ristics are expected to be important for the synthetic fusogenic pepti
de or the fusion peptide in hemagglutinin to induce membrane fusion.