Melittin, deuteromethylated on each of the four amino groups (Gly-1 Nα and Lys-7, 21, and 23 Nε), was prepared by reductive methylation using deuteroformaldehyde and NaBD3CN. Deuterium NMR spectra were obtained for the modified peptide (D-melittin) bound to phospholipid bilayers and erythrocyte ghosts. D-Melittin at 4 mol% (peptide:lipid) induced reversible transitions between extended bilayers and micelles at the phase-transition temperature in dimyristoylphosphatidylcholine (DMPC) bilayers. These changes in lipid morphology did not occur at 1 mol% D-melittin: DMPC and the peptide was highly motionally restricted in gel-phase lipid.
