ELASTICITY OF LIPID BILAYER INTERACTING WITH AMPHIPHILIC HELICAL PEPTIDES

Amphiphilic helical peptides exhibit an insertion transition when they interact with lipid bilayers. At low concentrations, the peptides adsorb at the hydrophilic-hydrophobic interface with the helical axes parallel to the bilayer surface. However, if the peptide concentration is above a critical value, a macroscopic fraction of the peptide molecules insert perpendicularly into the bilayer. The existence of a critical concentration for insertion is crucial to the peptides biological function. This phenomena can be understood in terms of the conventional theory of elasticity for a lipid bilayer.