5f12
WrbA in complex with FMN under crystallization conditions of WrbA-FMN-BQ structure (4YQE)
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] Publication Abstract from PubMedQuantum mechanical calculations using the Marcus equation are applied to compare the electron-transfer probability for two distinct crystal structures of the Escherichia coli protein WrbA, an FMN-dependent NAD(P)H:quinone oxidoreductase, with the bound substrate benzoquinone. The calculations indicate that the position of benzoquinone in a new structure reported here and solved at 1.33 A resolution is more likely to be relevant for the physiological reaction of WrbA than a previously reported crystal structure in which benzoquinone is shifted by approximately 5 A. Because the true electron-acceptor substrate for WrbA is not yet known, the present results can serve to constrain computational docking attempts with potential substrates that may aid in identifying the natural substrate(s) and physiological role(s) of this enzyme. The approach used here highlights a role for quantum mechanical calculations in the interpretation of protein crystal structures. Quantum Calculations Indicate Effective Electron Transfer between FMN and Benzoquinone in a New Crystal Structure of Escherichia coli WrbA.,Degtjarik O, Brynda J, Ettrichova O, Kuty M, Sinha D, Kuta Smatanova I, Carey J, Ettrich R, Reha D J Phys Chem B. 2016 May 31. PMID:27183467[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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