Crystallization and preliminary X-ray analysis of inorganic pyrophosphatase from the hyperthermophilic archaeon Pyrococcus horikoshii OT3

Inorganic pyrophosphatase (PPase; EC 3.6.1.1) from the hyperthermophile Pyrococcus horikoshii was crystallized by the hanging-drop vapour-diffusion method at pH 5.0 using polyethyleneglycol 4000 as the precipitant. The crystal belongs to space group P2₁2₁2, with unit-cell parameters a = 71.7, b = 86.5, c = 92.5 Å, α = β = γ = 90°. There are two molecules in the asymmetric unit. The crystals were stable during exposure to X-rays and a full set of X-ray diffraction data was collected to 2.7 Å resolution in-house.