Salivaricin 9, a new lantibiotic produced by Streptococcus salivarius

Microbiology (Reading). 2011 May;157(Pt 5):1290-1299. doi: 10.1099/mic.0.044719-0. Epub 2011 Feb 10.


Salivaricin 9 (Sal9) is a 2560 Da lantibiotic having just 46 % amino acid identity with its closest known homologue, the Streptococcus pyogenes lantibiotic SA-FF22. The Sal9 locus (designated siv) in Streptococcus salivarius strain 9 was partially sequenced and localized to an approximately 170 kb megaplasmid, which also harbours the locus for the lantibiotic salivaricin A4. The entire locus was fully characterized in the draft genome sequence of S. salivarius strain JIM8780 and shown to consist of eight genes, having the following putative functions: sivK, sensor kinase; sivR, response regulator; sivA, Sal9 precursor peptide; sivM, lantibiotic modification enzyme; sivT, ABC transporter involved in the export of Sal9 and concomitant cleavage of its leader peptide; and sivFEG, encoding lantibiotic self-immunity. Intriguingly, in contrast to strain 9, the siv locus was chromosomally located in strain JIM8780--the first lantibiotic locus shown not to be exclusively plasmid-associated in S. salivarius. Sal9-containing extracts specifically induced lantibiotic production in both strain 9 and strain JIM8780, indicating that Sal9 functions as a signal peptide for upregulation of its own biosynthesis. Screening representative strains of three streptococcal species (S. salivarius, S. pyogenes and S. mitis) for sivA indicated that it was present only in S. salivarius, with 12 of 28 tested S. salivarius positive. Since Sal9 was inhibitory to all tested S. pyogenes strains it appears to have potential as an important component of the bacteriocin armoury of S. salivarius probiotics intended to control S. pyogenes infections of the human oral cavity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-Bacterial Agents / biosynthesis*
  • Anti-Bacterial Agents / chemistry
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacteriocins / biosynthesis*
  • Bacteriocins / chemistry
  • Bacteriocins / genetics
  • Molecular Sequence Data
  • Protein Sorting Signals
  • Sequence Alignment
  • Streptococcus / chemistry
  • Streptococcus / genetics
  • Streptococcus / metabolism*


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Bacteriocins
  • Protein Sorting Signals

Associated data

  • GENBANK/DQ889747
  • GENBANK/GQ857551