title: The Flocculating Cationic Polypetide from Moringa oleifera Seeds Damages Bacterial Cell Membranes by Causing Membrane Fusion.
abstract: A cationic protein isolated from the seeds of the Moringa oleifera tree has been extensively studied for use in water treatment in developing countries and has been proposed for use in antimicrobial and therapeutic applications. However, the molecular basis for the antimicrobial action of this peptide, Moringa oleifera cationic protein (MOCP), has not been previously elucidated. We demonstrate here that a dominant mechanism of MOCP antimicrobial activity is membrane fusion. We used a combination of cryogenic electron microscopy (cryo-EM) and fluorescence assays to observe and study the kinetics of fusion of membranes in liposomes representing model microbial cells. We also conducted cryo-EM experiments on E. coli cells where MOCP was seen to fuse the inner and outer membranes. Coarse-grained molecular dynamics simulations of membrane vesicles with MOCP molecules were used to elucidate steps in peptide adsorption, stalk formation, and fusion between membranes.
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Kevin
authors.initials: K
authors.lastname: Shebek
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Allen B
authors.initials: AB
authors.lastname: Schantz
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Ian
authors.initials: I
authors.lastname: Sines
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Lauser
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Velegol
authors.affiliation: †Department of Chemical Engineering and ‡Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002412:Cations; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D005427:Flocculation; D005618:Fresh Water / Q000382:microbiology; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry / Q000648:ultrastructure; D008561:Membrane Fusion / Q000187:drug effects; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D029588:Moringa oleifera / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D012639:Seeds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D018508:Water Purification / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D008081:Liposomes; D010936:Plant Extracts; D010940:Plant Proteins