Processing of Clostridium difficile toxins

Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität Freiburg, Albertstrasse 25, D-79104 Freiburg, Germany Correspondence Klaus Aktories Klaus.Aktories{at}pharmakol.uni-freiburg.de The pathogenicity of Clostridium difficile depends on the large clostridial glucosylating toxins A and B (TcdA and TcdB). The proteins accomplish their own uptake by a modular structure comprising a catalytic and a binding/translocation domain. Based on a proteolytic processing step solely the catalytic domain reaches the cytosol. Within the cells, the glucosyltransferases inactivate small GTPases by mono- O -glucosylation. Here, a short overview is given regarding latest insights into the intramolecular processing, which is mediated by an intrinsic protease activity.