title: Interactions of antimicrobial peptide from C-terminus of myotoxin II with phospholipid mono- and bilayers.
abstract: Comparative studies of the effect of a short synthetic cationic peptide, pEM-2 (KKWRWWLKALAKK), derived from the C-terminus of myotoxin II from the venom of the snake Bothrops asper on phospholipid mono- and bilayers were performed by means of Langmuir Blodgett (LB) monolayer technique, atomic force microscopy and calcein leakage assay. Phospholipid mono- and bilayers composed of single zwitterionic or anionic phospholipids as well as lipid mixtures mimicking bacterial cell membrane were used. LB measurements indicate that the peptide binds to both anionic and zwitterionic phospholipid monolayers at low surface pressure but only to anionic at high surface pressure. Preferential interaction of the peptide with anionic phospholipid monolayer is also supported by a more pronounced change of the monolayer pressure/area isotherms induced by the peptide. AFM imaging reveals the presence of nanoscale aggregates in lipid/peptide mixture monolayers. At the same time, calcein leakage experiment demonstrated that pEM-2 induces stronger disruption of zwitterionic than anionic bilayers. Results of the study indicate that electrostatic interactions play a significant role in the initial recognition and binding of pEM-2 to the cell membrane. However, membrane rupturing activity of the peptide depends on interactions other than simple ionic attraction.
authors.affiliation: Department of Chemistry, Carleton University, Ottawa ON Canada.
authors.forename: Amy
authors.initials: A
authors.lastname: Won
authors.forename: Anatoli
authors.initials: A
authors.lastname: Ianoul
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D003435:Crotalid Venoms / Q000737:chemistry / Q000378:metabolism; D054501:Group II Phospholipases A2 / Q000737:chemistry* / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D010446:Peptide Fragments / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D030162:Reptilian Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D003435:Crotalid Venoms; D008051:Lipid Bilayers; D010446:Peptide Fragments; D010743:Phospholipids; D030162:Reptilian Proteins; C519619:pEM-2D peptide; D054501:Group II Phospholipases A2; C061056:myotoxin II, Bothrops asper