Carbohydrate recognition by Clostridium difficile toxin A

Nat Struct Mol Biol. 2006 May;13(5):460-1. doi: 10.1038/nsmb1084. Epub 2006 Apr 16.


Clostridium difficile TcdA is a large toxin that binds carbohydrates on intestinal epithelial cells. A 2-A resolution cocrystal structure reveals two molecules of alpha-Gal-(1,3)-beta-Gal-(1,4)-beta-GlcNAcO(CH(2))(8)CO(2)CH(3) binding in an extended conformation to TcdA. Residues forming key contacts with the trisaccharides are conserved in all seven putative binding sites in TcdA, suggesting a mode of multivalent binding that may be exploited for the rational design of novel therapeutics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Toxins / chemistry*
  • Bacterial Toxins / metabolism*
  • Carbohydrate Metabolism*
  • Carbohydrates / chemistry*
  • Clostridioides difficile / chemistry*
  • Clostridioides difficile / metabolism*
  • Enterotoxins / chemistry*
  • Enterotoxins / metabolism*
  • Hydrogen Bonding
  • Models, Molecular
  • Protein Binding
  • Protein Structure, Tertiary


  • Bacterial Toxins
  • Carbohydrates
  • Enterotoxins
  • tcdA protein, Clostridium difficile

Associated data

  • PDB/2G7C