Dual control of hydrogen cyanide biosynthesis by the global activator GacA in Pseudomonas aeruginosa PAO1

FEMS Microbiol Lett. 2001 Jun 12;200(1):73-8. doi: 10.1111/j.1574-6968.2001.tb10695.x.


The global response regulator GacA of Pseudomonas aeruginosa PAO1 positively controls the production of the quorum sensing signal molecule N-butanoyl-homoserine-lactone (C4-HSL) and hence the synthesis of several C4-HSL-dependent virulence factors, including hydrogen cyanide (HCN). This study presents evidence that GacA positively influences the transcription of the rhlI gene, specifying C4-HSL synthase, explaining the quorum sensing-dependent transcriptional control of the HCN biosynthetic genes (hcnABC). In addition, GacA was found to modulate hcn gene expression positively at a post-transcriptional level involving the hcnA ribosome-binding site. Thus, the activating effect of GacA on cyanogenesis results from both transcriptional and post-transcriptional mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Butyrolactone / analogs & derivatives
  • 4-Butyrolactone / biosynthesis
  • 4-Butyrolactone / genetics*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Gene Expression Regulation, Bacterial
  • Hydrogen Cyanide / metabolism*
  • Multienzyme Complexes / biosynthesis
  • Multienzyme Complexes / genetics*
  • Oxidoreductases / biosynthesis
  • Oxidoreductases / genetics*
  • Oxidoreductases Acting on CH-NH2 Group Donors
  • Pseudomonas aeruginosa / enzymology
  • Pseudomonas aeruginosa / genetics*
  • RNA Processing, Post-Transcriptional


  • Bacterial Proteins
  • GacA protein, Bacteria
  • Multienzyme Complexes
  • N-butyrylhomoserine lactone
  • RhiI protein, Rhizobium leguminosarum
  • Hydrogen Cyanide
  • Oxidoreductases
  • Oxidoreductases Acting on CH-NH2 Group Donors
  • glycine dehydrogenase (cyanide-forming)
  • 4-Butyrolactone