Titre
Structural genes for salicylate biosynthesis from chorismate in Pseudomonas aeruginosa.
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
Molecular and General Genetics
Auteur(s)
Serino, L.
Auteure/Auteur
Reimmann, C.
Auteure/Auteur
Baur, H.
Auteure/Auteur
Beyeler, M.
Auteure/Auteur
Visca, P.
Auteure/Auteur
Haas, D.
Auteure/Auteur
Liens vers les personnes
Liens vers les unités
ISSN
0026-8925
Statut éditorial
Publié
Date de publication
1995
Volume
249
Numéro
2
Première page
217
Dernière page/numéro d’article
228
Langue
anglais
Résumé
Salicylate is a precursor of pyochelin in Pseudomonas aeruginosa and both compounds display siderophore activity. To elucidate the salicylate biosynthetic pathway, we have cloned and sequenced a chromosomal region of P. aeruginosa PAO1 containing two adjacent genes, designated pchB and pchA, which are necessary for salicylate formation. The pchA gene encodes a protein of 52 kDa with extensive similarity to the chorismate-utilizing enzymes isochorismate synthase, anthranilate synthase (component I) and p-aminobenzoate synthase (component I), whereas the 11 kDa protein encoded by pchB does not show significant similarity with other proteins. The pchB stop codon overlaps the presumed pchA start codon. Expression of the pchA gene in P. aeruginosa appears to depend on the transcription and translation of the upstream pchB gene. The pchBA genes are the first salicylate biosynthetic genes to be reported. Salicylate formation was demonstrated in an Escherichia coli entC mutant lacking isochorismate synthase when this strain expressed both the pchBA genes, but not when it expressed pchB alone. By contrast, an entB mutant of E. coli blocked in the conversion of isochorismate to 2,3-dihydro-2,3-dihydroxybenzoate formed salicylate when transformed with a pchB expression construct. Salicylate formation could also be demonstrated in vitro when chorismate was incubated with a crude extract of P. aeruginosa containing overproduced PchA and PchB proteins; salicylate and pyruvate were formed in equimolar amounts. Furthermore, salicylate-forming activity could be detected in extracts from a P. aeruginosa pyoverdin-negative mutant when grown under iron limitation, but not with iron excess. Our results are consistent with a pathway leading from chorismate to isochorismate and then to salicylate plus pyruvate, catalyzed consecutively by the iron-repressible PchA and PchB proteins in P. aeruginosa.
Sujets
PID Serval
serval:BIB_C200CBBA56E1
PMID
Date de création
2008-01-24T13:00:43.324Z
Date de création dans IRIS
2025-05-21T03:58:37Z