InterPro domain: IPR010089

WrbA (tryptophan (W) repressor-binding protein) was discovered in Escherichia coli, where it was proposed to play a role in regulation of the tryptophan operon [ 1 ], which has been put in question since then [ 2 ]. Instead, WrbA has been shown to have FMN-dependent NAD(P)H:quinone oxidoreductase acivity [ 3 , 4 ]. A role in quinone detoxification has been proposed, supported by evidence suggesting its involvement in oxidative defense and/or cell signaling [ 5 , 6 ].

This entry also includes QR2 from Triphysaria versicolor. QR2 acts as a NAD(P)H:quinone oxidoreductase reducing quinones by a two-electron transfer mechanism [ 7 ].

1. A stationary-phase protein of Escherichia coli that affects the mode of association between the trp repressor protein and operator-bearing DNA. Proc. Natl. Acad. Sci. U.S.A. 90, 5796-800
2. Biochemical characterization of WrbA, founding member of a new family of multimeric flavodoxin-like proteins. J. Biol. Chem. 273, 20960-6
3. WrbA from Escherichia coli and Archaeoglobus fulgidus is an NAD(P)H:quinone oxidoreductase. J. Bacteriol. 188, 3498-506
4. Biphasic kinetic behavior of E. coli WrbA, an FMN-dependent NAD(P)H:quinone oxidoreductase. PLoS ONE 7, e43902
5. Six new candidate members of the alpha/beta twisted open-sheet family detected by sequence similarity to flavodoxin. Protein Sci. 3, 2185-93
6. An NADH:quinone oxidoreductase active during biodegradation by the brown-rot basidiomycete Gloeophyllum trabeum. Appl. Environ. Microbiol. 68, 2699-703
7. Quinone oxidoreductase message levels are differentially regulated in parasitic and non-parasitic plants exposed to allelopathic quinones. Plant J. 25, 375-87