Crystallization and preliminary X-ray diffraction studies of Murraya koenigii trypsin inhibitor.

A Kunitz-type trypsin inhibitor purified from the seeds of Murraya koenigii has been crystallized by the sitting-drop vapour-diffusion method using PEG 8000 as the precipitating agent. The crystals belong to the tetragonal space group P4(3)2(1)2, with unit-cell parameters a = b = 75.8, c = 150.9 A. The crystals contain two molecules in the asymmetric unit with a V(M) value of 2.5 A(3) Da(-1). Diffraction was observed to 2.65 A resolution and a complete data set was collected to 2.9 A resolution.