title: Pore-forming peptide of pathogenic Entamoeba histolytica.
abstract: A polypeptide that causes pore formation in target-cell membranes is implicated in the potent cytolytic activity of pathogenic Entamoeba histolytica. Pore-forming material was purified to apparent homogeneity by a multistep procedure, and its analysis by NaDodSO4/PAGE revealed one peptide of 4-5 kDa under nonreducing or under reducing conditions. Pore-forming activity was measured by depolarization of liposome membrane potential and was found to be optimally expressed at low pH. Active material preferentially inserted into negatively charged lipid vesicles. Treatment of purified amoeba peptide in solution or bound to liposomes with glutaraldehyde revealed oligomers upon NaDodSO4/PAGE, suggesting functionally relevant peptide-peptide interactions. The NH2-terminal amino acid sequence of the amoeba peptide was determined by protein sequencing and revealed a structural similarity to melittin, the membranolytic peptide of bee venom.
authors.affiliation: Department of Molecular Biology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Federal Republic of Germany.
authors.forename: M
authors.initials: M
authors.lastname: Leippe
authors.forename: S
authors.initials: S
authors.lastname: Ebel
authors.forename: O L
authors.initials: OL
authors.lastname: Schoenberger
authors.forename: R D
authors.initials: RD
authors.lastname: Horstmann
authors.forename: H J
authors.initials: HJ
authors.lastname: Müller-Eberhard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002845:Chromatography; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000302:isolation & purification / Q000502:physiology*; D007473:Ion Channels; D008555:Melitten / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000502:physiology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry / Q000302:isolation & purification*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D007473:Ion Channels; D008565:Membrane Proteins; D015800:Protozoan Proteins; C041670:amoebapore proteins, protozoan; D008555:Melitten