Crystallization and preliminary X-ray analysis of a complex between the Bowman-Birk trypsin inhibitor from barley and porcine pancreatic trypsin

A 1:2 complex between the Bowman-Birk trypsin inhibitor from barley seeds and porcine pancreatic trypsin has been crystallized at 291 K using polyethylene glycol as precipitant. The crystals belong to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 67.10, b = 88.38 and c = 203.65 Å. The asymmetric unit contains two monomers of the complex, with a corresponding V(m) of 2.41 29³ Da^-1 and a solvent content of 49%. Native data to 2.2 Å resolution have been collected at 100 K using synchrotron X-rays.