Figure 1.

Schematic of possible modes of interaction between amphipathic peptides and lipid bilayers. At low concentration, peptides adsorb to the surface of the lipid bilayer. At higher concentrations, a fraction of peptide molecules rotate to form pores. If the peptide is oriented perpendicular to the membrane, two models must be considered: the barrel-stave channels or the toroidal channels. Previous neutron scattering evidence led to the hypothesis of the toroidal form for magainin channels based on arguments about the amount of peptide available for pore formation.