Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin

PLoS One. 2015 Dec 29;10(12):e0145708. doi: 10.1371/journal.pone.0145708. eCollection 2015.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP Ribose Transferases / genetics
  • ADP Ribose Transferases / metabolism*
  • Actins / chemistry*
  • Actins / genetics
  • Actins / metabolism*
  • Adenosine Diphosphate Ribose / metabolism*
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Aspartic Acid / metabolism*
  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism*
  • Glutamic Acid / metabolism*
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Saccharomyces cerevisiae / genetics

Substances

  • Actins
  • Bacterial Toxins
  • iota toxin, Clostridium perfringens
  • Adenosine Diphosphate Ribose
  • Aspartic Acid
  • Glutamic Acid
  • ADP Ribose Transferases

Grants and funding

The article processing charge was funded by the German Research Foundation (DFG) and the Albert Ludwigs University Freiburg in the funding programme Open Access Publishing. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.