PMID:18728009

Citation	Zhang, YM, Frank, MW, Zhu, K, Mayasundari, A and Rock, CO (2008) PqsD is responsible for the synthesis of 2,4-dihydroxyquinoline, an extracellular metabolite produced by Pseudomonas aeruginosa. J. Biol. Chem. 283:28788-94
Abstract	2,4-Dihydroxyquinoline (DHQ) is an abundant extracellular metabolite of the opportunistic pathogen Pseudomonas aeruginosa that is secreted into growth medium in stationary phase to concentrations comparable with those of the Pseudomonas quinolone signal. Using a combination of biochemical and genetic approaches, we show that PqsD, a condensing enzyme in the pqs operon that is essential for Pseudomonas quinolone signal synthesis, accounts for DHQ formation in vivo. First, the anthraniloyl moiety is transferred to the active-site Cys of PqsD to form an anthraniloyl-PqsD intermediate, which then condenses with either malonyl-CoA or malonyl-acyl carrier protein to produce 3-(2-aminophenyl)-3-oxopropanoyl-CoA. This short-lived intermediate undergoes an intramolecular rearrangement to form DHQ. DHQ was produced by Escherichia coli coexpressing PqsA and PqsD, illustrating that these two proteins are the only factors necessary for DHQ synthesis. Thus, PqsD is responsible for the production of DHQ in P. aeruginosa.
Links	PubMed PMC2570881 Online version:10.1074/jbc.M804555200
Keywords	3-Oxoacyl-(Acyl-Carrier-Protein) Synthase/metabolism; 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase/physiology; Amino Acid Sequence; Animals; Bacterial Proteins/chemistry; Catalysis; Catalytic Domain; Cysteine/chemistry; Cystic Fibrosis/microbiology; Kinetics; Mice; Models, Chemical; Molecular Sequence Data; Pseudomonas aeruginosa/metabolism; Quinolines/chemistry; Sequence Homology, Amino Acid; Time Factors
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSEAE:PQSD	enables	GO:0016746: acyltransferase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
PSEAE:PQSD	involved_in	GO:0044550: secondary metabolite biosynthetic process	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
PSEAE:PQSD	enables	GO:0016746: transferase activity, transferring acyl groups	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
PSEAE:PQSD		GO:0004315: 3-oxoacyl-[acyl-carrier-protein] synthase activity	ECO:0000314:		F		Figure 2 shows DHQ formation by PqsD in Vitro. Mutant strains showed PqsD was a part of DHQ synthesis in vivo and was further tested in vitro. Anthraniloyl-CoA was produced in situ by PqsA and reacted with malonyl-CoA (a product of PqsD) to form DHQ as supported by TLC and LC-MS. These tests confirm DHQ formation when compared against the DHQ standard. Figure 7 shows the proposed mechanism for DHQ synthesis with the products of the Pqs gene.	complete CACAO 7692

References

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