Crystallization and preliminary analysis of xenobiotic reductase B from Pseudomonas fluorescens I-C

Single crystals have been obtained of xenobiotic reductase B (XenB), a flavoenzyme isolated and cloned from Pseudomonas fluorescens I-C. The enzyme catalyzes the NADPH-dependent elimination of nitrite from nitroglycerin with an approximately fivefold kinetic preference for the middle nitro group, primarily yielding 1,3-dinitroglycerol. X-ray diffraction data sets have been collected from native crystals to 2.3 A resolution. The space group is P4(1)2(1)2, with unit-cell parameters a = b = 140, c = 95.6 A. The asymmetric unit is likely to contain at least two XenB molecules (V(M) = 3.1 A(3) Da(-1), 60% solvent) and a molecular-replacement solution has been determined in order to solve the structure.