EFFECT OF SUCCINYLATION ON THE MEMBRANE-ACTIVITY AND CONFORMATION OF A SHORT CECROPIN A-MELITTIN HYBRID PEPTIDE

A 15-residue hybrid peptide (KWKLFKKIGAVLKVL-anmide) incorporating par tial sequences of cecropin A and melittin causes the release of carbox yfluoresceine encapsulated in phosphatidylcholine liposomes. Succinyla tion of the amino groups in the N-terminus and lysine side chains inhi bits the effect of this peptide on liposome permeability. Conformation al analysis of the parent peptide and its succinyl derivative by CD an d nmr indicates that both peptides form amphipathic alpha-helices in t he presence of hexafluoro-2-propanol, but only the unmodified peptide acquires a relevant level of alpha-helical conformation in the presenc e of liposomes. (C) 1994 John Wiley & Sons, Inc.