Preliminary X-ray crystallographic analysis of Bowman-Birk trypsin inhibitor from barley seeds

Bowman-Birk trypsin inhibitor from barley seeds has been crystallized at room temperature using polyethylene glycol as precipitant. The crystal is tetragonal, belonging to the space group P4₁2₁2 (or P4₃2₁2), with unit cell parameters of a = b = 62.48 and c = 94.63 Å. The asymmetric unit contains one molecule of Bowman-Birk trypsin inhibitor with corresponding crystal volume per protein mass (V_m) of 2.89 Å³ Da^-1 and the solvent content of 57% by volume. The crystals diffract to at least 1.9 Å Bragg spacing upon exposure to synchrotron X-rays. X-ray data to 1.9 Å have been collected from a native crystal.