title: Evidence for a modular structure of the homologous repetitive C-terminal carbohydrate-binding sites of Clostridium difficile toxins and Streptococcus mutans glucosyltransferases.
abstract: The homologous C-terminal repeats of Clostridium difficile toxins (ToxA and ToxB) and streptococcal glucosyltransferases appear to mediate protein-carbohydrate interactions at cellular binding sites with sugar moieties as substrates. A consensus sequence of 134 repeating units from gram-positive bacteria indicates that these repeats have a modular design with (i) a stretch of aromatic amino acids proposed to be involved in the primary carbohydrate-protein interaction, (ii) an amplification of this interaction by repetition of the respective sequences, and (iii) a second domain, not characterized, that is responsible for carbohydrate specificity.
authors.affiliation: Institut für Medizinische Mikrobiologie, Johannes-Gutenberg-Universität, Mainz, Federal Republic of Germany.
authors.forename: C
authors.initials: C
authors.lastname: von Eichel-Streiber
authors.forename: M
authors.initials: M
authors.lastname: Sauerborn
authors.forename: H K
authors.initials: HK
authors.lastname: Kuramitsu
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D016360:Clostridioides difficile / Q000737:chemistry*; D016384:Consensus Sequence; D003603:Cytotoxins / Q000737:chemistry*; D004768:Enterotoxins / Q000737:chemistry* / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013295:Streptococcus mutans / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D005964:Glucosyltransferases