Depth of bilayer penetration and effects on lipid mobility conferred by themembrane-active peptidesmagainin, melit-tin, and a hydrophobic helical sequence KKA(LA)7KK (denoted KAL), were investigated by colorimetric and time-resolved fluorescence techniques in biomimetic phos-pholipid/poly(diacetylene)vesicles. The experiments dem-onstrated that the extent of bilayer permeation and peptide localization within the membrane was dependent upon the bilayer composition, and that distinct dynamic modifica-tions were induced by each peptide within the head-group environment of the phospholipids
