Crystal structure of the NADH:quinone oxidoreductase WrbA from Escherichia coli.
Andrade, S.L., Patridge, E.V., Ferry, J.G., Einsle, O.(2007) J Bacteriol 189: 9101-9107
- PubMed: 17951395 
- DOI: https://doi.org/10.1128/JB.01336-07
- Primary Citation of Related Structures:  
3B6I, 3B6J, 3B6K, 3B6M - PubMed Abstract: 
The 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.
Organizational Affiliation: 
Institute for Microbiology and Genetics, Georg August University Göttingen, Justus von Liebig Weg 11, 37077 Göttingen, Germany. susana.andrade@bio.uni-goettingen.de