Inactivation of srtA gene of Streptococcus mutans inhibits dextran-dependent aggregation by glucan-binding protein C

Oral Microbiol Immunol. 2004 Feb;19(1):57-60. doi: 10.1046/j.0902-0055.2003.00104.x.


A sortase-deficient mutant of Streptococcus mutans was prepared by insertional inactivation of a sortase gene (srtA). The srtA mutant was defective in cell wall-anchoring of two surface proteins 200 and 75 kDa in size. A previous study has shown that the 200 kDa protein is a surface protein antigen PAc and that the sortase catalyzes cell wall-anchoring of PAc in S. mutans. In this study another surface protein 75 kDa in size was examined by immunologic and physiologic methods. Western blot analysis with a specific antiserum showed that the 75 kDa protein was a surface protein, glucan-binding protein C. The protein was overexpressed under a stress condition including a sublethal concentration of tetracycline. The srtA mutant cells also lost the ability of dextran-dependent aggregation. These results suggest that the S. mutans sortase mediates cell wall-anchoring of the glucan-binding protein C and dextran-dependent aggregation of this organism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / genetics
  • Aminoacyltransferases / genetics*
  • Antigens, Bacterial / genetics
  • Bacterial Adhesion / genetics*
  • Bacterial Proteins / genetics*
  • Carrier Proteins / genetics*
  • Cysteine Endopeptidases
  • Dextrans / metabolism
  • Epitopes / genetics
  • Gene Expression Regulation, Bacterial / genetics
  • Gene Silencing*
  • Glucans / genetics*
  • Humans
  • Lectins
  • Membrane Glycoproteins*
  • Mutation / genetics
  • Streptococcus mutans / genetics*


  • Adhesins, Bacterial
  • Antigens, Bacterial
  • Bacterial Proteins
  • Carrier Proteins
  • Dextrans
  • Epitopes
  • Glucans
  • Lectins
  • Membrane Glycoproteins
  • S-layer proteins
  • glucan-binding proteins
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases