Identification of subtilisin, Epr and Vpr as enzymes that produce CSF, an extracellular signalling peptide of Bacillus subtilis

Mol Microbiol. 2007 Sep;65(5):1321-33. doi: 10.1111/j.1365-2958.2007.05869.x. Epub 2007 Jul 31.


Cell-cell communication regulates many important processes in bacteria. Gram-positive bacteria use peptide signals for communication, such as the Phr pentapeptides of Bacillus subtilis. The Phr pentapeptides are secreted with a pro domain that is cleaved to produce an active signalling peptide. To identify the protease(s) involved in production of the mature Phr signalling peptides, we developed assays for detecting cleavage of one of the B. subtilis Phr pentapeptides, CSF, from the proCSF precursor. Using both a cellular and a mass spectrometric approach, we determined that a sigma-H-regulated, secreted, serine protease(s) cleaved proCSF to CSF. Mutants lacking the three proteases that fit these criteria, subtilisin, Epr and Vpr, had a defect in CSF production. Purified subtilisin and Vpr were shown to be capable of processing proCSF as well as at least one other Phr peptide produced by B. subtilis, PhrA, but they were not able to process the PhrE signalling peptide of B. subtilis, indicating that there are probably other unidentified proteases involved in Phr peptide production. Subtilisin, Epr and Vpr are members of the subtilisin family of proteases that are widespread in bacteria, suggesting that many bacterial species may be capable of producing Phr signalling peptides.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Communication / physiology*
  • Molecular Sequence Data
  • Peptides / genetics
  • Peptides / metabolism*
  • Protein Precursors / genetics
  • Protein Precursors / metabolism
  • Sequence Alignment
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism*
  • Sigma Factor / metabolism
  • Signal Transduction / physiology
  • Subtilisin / genetics
  • Subtilisin / metabolism*


  • Bacterial Proteins
  • Peptides
  • Protein Precursors
  • Sigma Factor
  • Epr serine proteinase
  • Serine Endopeptidases
  • Vpr protein, Bacillus subtilis
  • Subtilisin