3b6j
WrbA from Escherichia coli, NADH complex
Structural highlights
FunctionNQOR_ECOLI It seems to function in response to environmental stress when various electron transfer chains are affected or when the environment is highly oxidizing. It reduces quinones to the hydroquinone state to prevent interaction of the semiquinone with O2 and production of superoxide. It prefers NADH over NADPH.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe flavoprotein WrbA, originally described as a tryptophan (W) repressor-binding protein in Escherichia coli, has recently been shown to exhibit the enzymatic activity of a NADH:quinone oxidoreductase. This finding points toward a possible role in stress response and in the maintenance of a supply of reduced quinone. We have determined the three-dimensional structure of the WrbA holoprotein from E. coli at high resolution (1.66 A), and we observed a characteristic, tetrameric quaternary structure highly similar to the one found in the WrbA homologs of Deinococcus radiodurans and Pseudomonas aeruginosa. A similar tetramer was originally observed in an iron-sulfur flavoprotein involved in the reduction of reactive oxygen species. Together with other, recently characterized proteins such as YhdA or YLR011wp (Lot6p), these tetrameric flavoproteins may constitute a large family with diverse functions in redox catalysis. WrbA binds substrates at an active site that provides an ideal stacking environment for aromatic moieties, while providing a pocket that is structured to stabilize the ADP part of an NADH molecule in its immediate vicinity. Structures of WrbA in complex with benzoquinone and NADH suggest a sequential binding mechanism for both molecules in the catalytic cycle. Crystal structure of the NADH:quinone oxidoreductase WrbA from Escherichia coli.,Andrade SL, Patridge EV, Ferry JG, Einsle O J Bacteriol. 2007 Dec;189(24):9101-7. Epub 2007 Oct 19. PMID:17951395[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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