Crystallization and preliminary X-ray diffraction studies of hyperthermostable glutamate dehydrogenase from Thermococcus profundus

Recombinant glutamate dehydrogenase from a hyperthermophilic archaeon. Thermococcus profundus, was crystallized in the presence of both polyethylene glycol 8000 and lithium sulfate. Four types of crystals having different morphologies appeared in the crystallization trials; however, only one type was suitable for X-ray crystal structure analysis. The crystal belonged to the monoclinic space group P2₁ and the unit-cell parameters were a = 112.99, b = 163.70, c = 133.07 Å, β = 113.46°at 110 K. The calculated V(M) value of 3.42 ų Da^-1 was acceptable when one hexamer of the enzyme, which was the physiological functional unit, occupied a crystallographic asymmetric unit. X-ray diffraction intensity data were collected to a resolution of 2.25 Å with good statistics at the BL44B2 beamline of SPring-8.