Crystallization and preliminary X-ray analysis of NADH:rubredoxin oxidoreductase from Clostridium acetobutylicum

NADH:rubredoxin oxidoreductase (NROR), an O₂-inducible protein, is a versatile electron donor for scavengers of O₂ and reactive oxygen species (ROS) in Clostridium acetobutylicum. Recombinant NROR was overexpressed in Escherichia coli and purified to homogeneity; it was subsequently crystallized using the sitting-drop vapour-diffusion method at 293 K. Preliminary crystallo­graphic analysis revealed that the crystals belonged to space group P4₁22 or P4₃22, with unit-cell parameters a = b = 98.6, c = 88.3 Å, and diffracted to 2.1 Å resolution. Assuming that the crystals contained one molecule per asymmetric unit, the Matthews coefficient was calculated to be 2.7 Å³ Da^-1 and the solvent content to be 54.1%.