title: Identification of the channel-forming domain of Clostridium perfringens Epsilon-toxin (ETX).
abstract: Epsilon-toxin (ETX) is a potent toxin produced by Clostridium perfringens strains B and D. The bacteria are important pathogens in domestic animals and cause edema mediated by ETX. This toxin acts most likely by heptamer formation and rapid permeabilization of target cell membranes for monovalent anions and cations followed by a later entry of calcium. In this study, we compared the primary structure of ETX with that of the channel-forming stretches of a variety of binding components of A-B-types of toxins such as Anthrax protective antigen (PA), C2II of C2-toxin and Ib of Iota-toxin and found a remarkable homology to amino acids 151-180 of ETX. Site-directed mutagenesis of amino acids within the putative channel-forming domain resulted in changes of cytotoxicity and effects on channel characteristics in lipid bilayer experiments including changes of selectivity and partial channel block by methanethiosulfonate (MTS) reagents and antibodies against His(6)-tags from the trans-side of the lipid bilayer membranes.
authors.affiliation: Department of Biotechnology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Knapp
authors.forename: Elke
authors.initials: E
authors.lastname: Maier
authors.forename: Roland
authors.initials: R
authors.lastname: Benz
authors.forename: Blandine
authors.initials: B
authors.lastname: Geny
authors.forename: Michel R
authors.initials: MR
authors.lastname: Popoff
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D003016:Clostridium perfringens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D010449:Peptide Mapping / Q000379:methods; D010539:Permeability; D020836:Protein Structure, Quaternary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D017386:Sequence Homology, Amino Acid
chemical_list: D001427:Bacterial Toxins; C039811:Clostridium perfringens epsilon-toxin; D008051:Lipid Bilayers