Crystallization and preliminary X-ray crystallographic study of ribosome-inactivating protein from barley seeds

Ribosome-inactivating protein from barley seeds has been crystallized using polyethylene glycol as precipitant. The crystal belongs to the monoclinic space group C2, with unit-cell parameters a = 88.36, b = 62.59, c = 53.18 Å and β = 108.62°. The asymmetric unit contains one molecule of ribosome-inactivating protein with a corresponding crystal volume per protein mass (V_m) of 2.32 ų Da⁻¹ and a solvent content of 47% by volume. The crystal diffracts to about 2.3 Å with X-rays from a rotating-anode source and is very stable in the X-ray beam. X-ray data (nearly complete to 2.4 Å Bragg spacing) have been collected from a native crystal.