title: Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin.
abstract: Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia.
authors.affiliation: Gamaleya Research Institute, Moscow, Russia.|Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Belyy
authors.affiliation: Gamaleya Research Institute, Moscow, Russia.
authors.forename: Irina
authors.initials: I
authors.lastname: Tabakova
authors.affiliation: Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Lang
authors.affiliation: Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jank
authors.affiliation: Gamaleya Research Institute, Moscow, Russia.|Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany.
authors.forename: Yury
authors.initials: Y
authors.lastname: Belyi
authors.affiliation: Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany.|Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany.|Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Aktories
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001224:Aspartic Acid / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000235:genetics
chemical_list: D000199:Actins; D001427:Bacterial Toxins; C050737:iota toxin, Clostridium perfringens; D000246:Adenosine Diphosphate Ribose; D001224:Aspartic Acid; D018698:Glutamic Acid; D036002:ADP Ribose Transferases