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Allen Orville - Xenobiotic Reductases (XenA & XenB)

Allen Orville 's research interests explained in more detail:

The reductive nitrite elimination from explosive compounds is catalyzed by two FMN-dependent, xenobiotic reductases (XenA or XenB). These regiospecific enzymes were cloned from two Pseudomonads isolated at the same munitions manufacturing site. The enzyme activity enables the microbes to obtain all their nitrogen requirements from nitroglycerin. The two enzymes also transform a number of additional nitrocompounds in vitro. To better understand these characteristics, we solved the crystal structures for both XenA and XenB. The 1.6 Å resolution structure of XenA reveals a dimer of (??)8-TIM barrels, but the 2.2 Å resolution structure for XenB is a monomer. We have also generated models of the reduced enzyme-nitroglycerin complexes by molecular dynamics. The results with both XenA and XenB reveal differences in enzyme-ligand hydrogen bonding. These differences correlate remarkably well with the regiospecific differences observed for nitrite elimination from nitroglycerin and reduction of TNT by the two enzymes.

  • Supported by: American Chemical Society, Petroleum Research Fund (40310-G4), A.M.O. (PI) and
    American Heart Association Grant in Aid (0555286B), A.M.O. (PI).
  • Orville A.M., Manning L., Blehert D.S., Fox B.G. and Chambliss G.H.
    Crystallization and preliminary analysis of xenobiotic reductase B and ligand complexes from Pseudomonas fluorescens I-C.
    Acta Crystallography, D60:1289-1291 (2004).   PubMed
  • Orville A.M., Manning L., Blehert D.S., Studts J.M., Fox B.G. and Chambliss G.H.
    Crystallization and preliminary analysis of xenobiotic reductase A and ligand complexes from Pseudomonas putida II-B.
    Acta Crystallography, D60:957-961 (2004).   PubMed
  • Orville A.M., Nagpal A., Manning L., Blehert D.S., Valley M.P., Chambliss G.H., Fox B.G. and Fitzpatrick P.F.
    Structural Perspective on Nitrite Elimination of Organic Nitrochemicals by Flavoenzymes.
    in Flavins and Flavoproteins 2005, (T. Nishino, R. Miura, M. Tanokura, K. Fukui, edts)
    ARchiTect Inc. 827-840 (2005).