The Pseudomonas Siderophore Quinolobactin Is Synthesized From Xanthurenic Acid, an Intermediate of the Kynurenine Pathway

Mol Microbiol. 2004 Apr;52(2):371-84. doi: 10.1111/j.1365-2958.2004.03999.x.


To cope with iron deficiency fluorescent pseudomonads produce pyoverdines which are complex peptidic siderophores that very efficiently scavenge iron. In addition to pyoverdine some species also produce other siderophores. Recently, it was shown that Pseudomonas fluorescens ATCC 17400 produces the siderophore quinolobactin, an 8-hydroxy-4-methoxy-2-quinoline carboxylic acid (Mossialos, D., Meyer, J.M., Budzikiewicz, H., Wolff, U., Koedam, N., Baysse, C., Anjaiah, V., and Cornelis, P. (2000) Appl Environ Microbiol 66: 487-492). The entire quinolobactin biosynthetic, transport and uptake gene cluster, consisting out of two operons comprising 12 open reading frames, was cloned and sequenced. Based on the genes present and physiological complementation assays a biosynthetic pathway for quinolobactin is proposed. Surprisingly, this pathway turned out to combine genes derived from the eukaryotic tryptophan-xanthurenic acid branch of the kynurenine pathway and from the pathway for the biosynthesis of pyridine-2,6-bis(thiocarboxylic acid) from P. stutzeri, PDTC. These results clearly show the involvement of the tryptophan-kynurenine-xanthurenic acid pathway in the synthesis of an authentic quinoline siderophore.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • DNA Transposable Elements
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Iron / metabolism*
  • Iron Chelating Agents / metabolism
  • Iron Chelating Agents / pharmacology
  • Kynurenine / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Pseudomonas fluorescens / drug effects
  • Pseudomonas fluorescens / genetics
  • Pseudomonas fluorescens / growth & development
  • Pseudomonas fluorescens / metabolism*
  • Quinolines*
  • Siderophores / biosynthesis*
  • Siderophores / chemistry
  • Siderophores / isolation & purification
  • Siderophores / metabolism
  • Tryptophan / metabolism
  • Xanthurenates / metabolism*
  • Xanthurenates / pharmacology


  • DNA Transposable Elements
  • Iron Chelating Agents
  • Quinolines
  • Siderophores
  • Xanthurenates
  • quinolobactin
  • Kynurenine
  • xanthurenic acid
  • Tryptophan
  • Iron

Associated data

  • GENBANK/AY271621