Regulation of Streptococcus mutans PTSBio by the transcriptional repressor NigR

M. Vujanac, V. S. Iyer, M. Sengupta, Dragana Ajdic

Research output: Contribution to journalArticle


Streptococcus mutans is implicated in human dental caries, and the carbohydrate metabolism of this organism plays an important role in the formation of this disease. Carbohydrate transport and metabolism are essential for the survival of S.mutans in the oral cavity. It is known that a unique phosphoenolpyruvate-sugar phosphotransferase system PTSB io of S.mutans UA159 is expressed in sucrose-grown biofilms (Mol Oral Microbiol 28: 2013; 114). In this study we analyzed the transcriptional regulation of the operon (OB io) encoding the PTSB io and showed that it was repressed by NigR, a LacI-like transcriptional regulator. Using electro-mobility shift assay, we described two operators to which NigR bound with different affinities. We also identified the transcriptional start site and showed that one of the operators overlaps with the promoter and presumably represses initiation of transcription. Mutational analyses revealed the key nucleotides in the operators required for high-affinity binding of NigR. PTSB io is expressed in S.mutans biofilms so understanding its regulation may provide improved strategies for caries treatment and prevention.

Original languageEnglish (US)
Pages (from-to)280-294
Number of pages15
JournalMolecular Oral Microbiology
Issue number4
StatePublished - Aug 1 2015



  • Streptococcus mutans
  • Dental caries
  • Phosphotransferase system
  • Transcriptional regulation

ASJC Scopus subject areas

  • Immunology
  • Microbiology
  • Microbiology (medical)
  • Dentistry(all)

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