EC Number   |
General Information |
Reference |
|---|
  1.14.14.B14 | evolution |
enzyme PqsL belongs to the class A flavoprotein monooxygenases |
-, 765050 |
| 1.14.14.B14 | metabolism |
2-alkyl-4-hydroxyquinoline-N-oxide (AQNO) biosynthesis involves the enzymes encoded by the pqsABCDE operon, which mediate 2-alkyl-4-hydroxyquinoline biosynthesis from anthranilic acid and activated fatty acids, and additionally requires PqsL, a putative flavin-dependent monooxygenase encoded by a presumably monocistronic gene. AQNO biosynthesis branches off from 2-ABA or an immediate downstream intermediate. Biosynthesis of alkyl quinolones in Pseudomonas aeruginosa and possible reactions for 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) synthesis. FAD reductase HpaC supports PqsL activity in the coupled PqsL/PqsBC assay. Deletion of hpaC in Pseudomonas aeruginosa strain PAO1 influences the HQNO to HHQ ratio |
-, 765050 |
| 1.14.14.B14 | more |
PqsL structurally resembles class A flavoprotein monooxygenases such as p-hydroxybenzoate 3-hydroxylase (pHBH, EC 1.14.13.2) and 3-hydroxybenzoate 6-hydroxylase (EC 1.14.13.24). But unlike related enzymes, PqsL hydroxylates a primary aromatic amine group, and it does not use NAD(P)H as cosubstrate, but unexpectedly requires reduced flavin as electron donor. A structural comparison with pHBH, the model enzyme of class A flavoprotein monooxygenases, reveals that structural features associated with NAD(P)H binding are missing in PqsL |
-, 765050 |
| 1.14.14.B14 | physiological function |
alkyl hydroxyquinoline N-oxides (AQNOs) are antibiotic compounds produced by the opportunistic bacterial pathogen Pseudomonas aeruginosa. They are products of the alkyl quinolone (AQ) biosynthetic pathway, which also generates the quorum-sensing molecules 2-heptyl-4(1H)-quinolone (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS). PqsL is the key enzyme for AQNO production. PqsL is active toward 2-aminobenzoylacetate (2-ABA), the central intermediate of the AQ pathway, and forms the unstable compound 2-hydroxylaminobenzoylacetate, which is preferred over 2-ABA as a substrate of the downstream enzyme PqsBC. Although 2-heptyl-3-hydroxy-4(1H)-quinolone (Pseudomonas quinolone signal, PQS) and its immediate biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) mainly serve as quorum sensing signals, contributing to the control of virulence gene expression, 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) acts as a toxin against both microorganisms and eukaryotic cells. PqsL is the key enzyme for biosynthesis of HQNO, it catalyzes the N-oxidation of a biosynthetic precursor molecule other than HHQ |
-, 765050 |
