title: Melittin peptides exhibit different activity on different cells and model membranes.
abstract: Melittin (MLT) is a lytic peptide with a broad spectrum of activity against both eukaryotic and prokaryotic cells. To understand the role of proline and the thiol group of cysteine in the cytolytic activity of MLT, native MLT and cysteine-containing analogs were prepared using solid phase peptide synthesis. The antimicrobial and cytolytic activities of the monomeric and dimeric MLT peptides against different cells and model membranes were investigated. The results indicated that the proline residue was necessary for antimicrobial activity and cytotoxicity and its absence significantly reduced lysis of model membranes and hemolysis. Although lytic activity against model membranes decreased for the MLT dimer, hemolytic activity was increased. The native peptide and the MLT-P14C monomer were mainly unstructured in buffer while the dimer adopted a helical conformation. In the presence of neutral and negatively charged vesicles, the helical content of the three peptides was significantly increased. The lytic activity, therefore, is not correlated to the secondary structure of the peptides and, more particularly, on the propensity to adopt helical conformation.
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
authors.forename: Elaheh
authors.initials: E
authors.lastname: Jamasbi
authors.forename: Steven
authors.initials: S
authors.lastname: Batinovic
authors.forename: Robyn A
authors.initials: RA
authors.lastname: Sharples
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: Sani
authors.forename: Roy Michael
authors.initials: RM
authors.lastname: Robins-Browne
authors.forename: John D
authors.initials: JD
authors.lastname: Wade
authors.forename: Frances
authors.initials: F
authors.lastname: Separovic
authors.forename: Mohammed Akhter
authors.initials: MA
authors.lastname: Hossain
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D008555:Melitten / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D008555:Melitten