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Actin-specific ADP-ribosyltransferase produced by a Clostridium difficile strain

M R Popoff1, E J Rubin, D M Gill

  • 1Unité des Antigènes Bactériens, UA Centre National de la Recherche Scientifique, Paris, France.

Infection and Immunity
|September 1, 1988
PubMed

Insights

A new ADP-ribosyltransferase (CDT) from Clostridium difficile modifies cell actin, similar to other toxins. This enzyme lacks direct toxicity but impacts actin modification in cells treated with C. difficile toxin B.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Toxicology

Background:

  • Clostridium species produce various toxins affecting host cells.
  • ADP-ribosyltransferases are enzymes that modify cellular proteins, impacting cell function.
  • Clostridium difficile toxins A and B are well-known virulence factors.

Purpose of the Study:

  • To screen Clostridium species for novel ADP-ribosyltransferase activities.
  • To characterize a newly identified ADP-ribosyltransferase from Clostridium difficile.
  • To investigate the relationship between this enzyme and known toxins.

Main Methods:

  • Screening of culture supernatants from Clostridium species.
  • Biochemical characterization of the novel ADP-ribosyltransferase (molecular weight, isoelectric point).
  • Assays for cytotoxic and lethal activity.
  • In vitro ADP-ribosylation assays using cell actin.
  • Immunoblot analysis with antibodies against the novel enzyme.

Main Results:

  • A novel ADP-ribosyltransferase (CDT) was identified in Clostridium difficile strain CD196.
  • CDT (43 kDa, pI 7.8) covalently modifies cell actin.
  • CDT showed no direct cytotoxic or lethal activity.
  • CDT is distinct from C. difficile toxins A and B, and C. botulinum C2 toxin component I.
  • Pre-treatment of Vero cells with C. difficile toxin B reduced actin's ADP-ribosylation by CDT.
  • Antibodies to CDT recognized a similar protein in Clostridium perfringens type E supernatant.

Conclusions:

  • Clostridium difficile produces a novel actin-modifying ADP-ribosyltransferase, CDT.
  • CDT's activity is distinct from known C. difficile toxins but may be influenced by Toxin B.
  • CDT shares antigenic similarities with the iota toxin component from Clostridium perfringens type E.

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