PqsL uses reduced flavin to produce 2-hydroxylaminobenzoylacetate, a preferred PqsBC substrate in alkyl quinolone biosynthesis in .

Alkyl hydroxyquinoline -oxides (AQNOs) are antibiotic compounds produced by the opportunistic bacterial pathogen They are products of the alkyl quinolone (AQ) biosynthetic pathway, which also generates the quorum-sensing molecules 2-heptyl-4(1)-quinolone (HHQ) and 2-heptyl-3-hydroxy-4(1)-quinolone (PQS). Although the enzymatic synthesis of HHQ and PQS had been elucidated, the route by which AQNOs are synthesized remained elusive. Here, we report on PqsL, the key enzyme for AQNO production, which structurally resembles class A flavoprotein monooxygenases such as -hydroxybenzoate 3-hydroxylase (pHBH) and 3-hydroxybenzoate 6-hydroxylase.

PqsBC, a Condensing Enzyme in the Biosynthesis of the Pseudomonas aeruginosa Quinolone Signal: CRYSTAL STRUCTURE, INHIBITION, AND REACTION MECHANISM.

Pseudomonas aeruginosaproduces a number of alkylquinolone-type secondary metabolites best known for their antimicrobial effects and involvement in cell-cell communication. In the alkylquinolone biosynthetic pathway, the β-ketoacyl-(acyl carrier protein) synthase III (FabH)-like enzyme PqsBC catalyzes the condensation of octanoyl-coenzyme A and 2-aminobenzoylacetate (2-ABA) to form the signal molecule 2-heptyl-4(1H)-quinolone. PqsBC, a potential drug target, is unique for its heterodimeric arrangement and an active site different from that of canonical FabH-like enzymes.