6FHO

Crystal structure of pqsL, a probable FAD-dependent monooxygenase from Pseudomonas aeruginosa - new refinement

Summary for 6FHO

• Entry DOI: 10.2210/pdb6fho/pdb
• Descriptor: Probable FAD-dependent monooxygenase, FLAVIN-ADENINE DINUCLEOTIDE (3 entities in total)
• Functional Keywords: oxidoreductase, pqsl, flavoprotein monooxygenase
• Biological source: Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)
• Total number of polymer chains: 1
• Total formula weight: 44874.57

Authors

Belviso, B.D.,Drees, S.L.,Ernst, S.,Jagmann, N.,Hennecke, U.,Fetzner, S. (deposition date: 2018-01-15, release date: 2018-04-25, Last modification date: 2024-05-08)

Primary citation

Drees, S.L.,Ernst, S.,Belviso, B.D.,Jagmann, N.,Hennecke, U.,Fetzner, S.
PqsL uses reduced flavin to produce 2-hydroxylaminobenzoylacetate, a preferred PqsBC substrate in alkyl quinolone biosynthesis inPseudomonas aeruginosa.
J. Biol. Chem., 293:9345-9357, 2018

PubMed Abstract: 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. However, we found that unlike related enzymes, PqsL hydroxylates a primary aromatic amine group, and it does not use NAD(P)H as cosubstrate, but unexpectedly required reduced flavin as electron donor. We also observed that PqsL is active toward 2-aminobenzoylacetate (2-ABA), the central intermediate of the AQ pathway, and forms the unstable compound 2-hydroxylaminobenzoylacetate, which was preferred over 2-ABA as substrate of the downstream enzyme PqsBC. reconstitution of the PqsL/PqsBC reaction was feasible by using the FAD reductase HpaC, and we noted that the AQ:AQNO ratio is increased in an deletion mutant of PAO1 compared with the ratio in the WT strain. A structural comparison with pHBH, the model enzyme of class A flavoprotein monooxygenases, revealed that structural features associated with NAD(P)H binding are missing in PqsL. Our study completes the AQNO biosynthetic pathway in , indicating that PqsL produces the unstable product 2-hydroxylaminobenzoylacetate from 2-ABA and depends on free reduced flavin as electron donor instead of NAD(P)H.

PubMed: 29669807
DOI: 10.1074/jbc.RA117.000789

Experimental method

X-RAY DIFFRACTION (1.75 Å)