Specific activation of the Bacillus quorum-sensing systems by isoprenylated pheromone variants

Mireille Ansaldi, Darja Marolt, Tina Stebe, Ines Mandic-Mulec, David Dubnau

Research output: Contribution to journalArticlepeer-review

122 Scopus citations


Natural genetic competence in Bacillus subtilis is controlled by quorum-sensing (QS). The ComP-ComA two-component system detects the signalling molecule ComX, and this signal is transduced by a conserved phosphotransfer mechanism. ComX is synthesized as an inactive precursor and is then cleaved and modified by ComQ before export to the extracellular environment. ThecomQXP′ loci of a set of natural Bacillus isolates have been sequenced and shown to possess a striking polymorphism that determines specific patterns of both activation and inhibition of the quorum-sensing response. We have developed a simple purification method for the modified peptide signalling pheromones allowing the characterization of four distinct ComX molecules representing different pherotypes. Genetic and biochemical evidence demonstrate that all the ComX variants are isoprenylated by the post-translational modification of a conserved tryptophan residue and that the modifications on the ComX peptide backbones vary in mass among the various phero-types. These results give new insights into peptidemediated quorum-sensing signalling in Gram-positive bacteria and emphasize the role of isoprenylation in bacterial signal transduction.

Original languageEnglish (US)
Pages (from-to)1561-1573
Number of pages13
JournalMolecular microbiology
Issue number6
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology


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