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A Stereospecific Pathway Diverts beta-Oxidation Intermediates to the Biosynthesis of Rhamnolipid Biosurfactants

Abdel-Mawgoud, Ahmad Mohammad; Lépine, François; Déziel, Éric (2014). A Stereospecific Pathway Diverts beta-Oxidation Intermediates to the Biosynthesis of Rhamnolipid Biosurfactants Chemistry and Biology , vol. 21 , nº 1. p. 156-164. DOI: 10.1016/j.chembiol.2013.11.010.

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Résumé

Rhamnolipids are multipurpose surface-active molecules produced by the bacterium Pseudomonas aeruginosa from L-rhamnose and R-3-hydroxyalkanoate (C10+/-2) precursors. R-3-hydroxyalkanoate precursor is believed to be synthesized de novo. We demonstrate, however, that beta-oxidation is the predominant source of this precursor. Inhibition of beta-oxidation sharply decreases rhamnolipids production, even when using a nonfatty acid carbon source (glycerol). Isotope tracing shows that beta-oxidation intermediates are direct precursors of rhamnolipids. A mutant-based survey revealed an operon coding for enoyl-CoA hydratases/isomerases (ECH/I), named RhlYZ, implicated in rhamnolipids production via an axial role in 3-hydroxyalkanoate synthesis. In vitro, RhlZ is an R-ECH/I transforming 2-decenoyl-CoA, a beta-oxidation intermediate, into R-3-hydroxydecanoyl-CoA, the potential rhamnolipids precursor. Interestingly, polyhydroxyalkanoates share with rhamnolipids the RhlYZ-generated R-3-hydroxyalkanoates pool, as demonstrated by the decrease of polyhydroxyalkanoates upon mutation of rhlYZ and the increase of rhamnolipids in a polyhydroxyalkanoates-defective mutant.

Type de document:
Mots-clés libres: AERUGINOSA STRAIN 57RP, PSEUDOMONAS-AERUGINOSA, ESCHERICHIA-COLI, ENOYL-COENZYME, ACID, POLYHYDROXYALKANOATES, INHIBITION, HYDRATASES, PRECURSORS, EXPRESSION
Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 29 avr. 2014 18:50
Dernière modification: 29 avr. 2014 18:50
URI: http://espace.inrs.ca/id/eprint/2183

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