Heterogeneous nucleation helps the search for initial crystallization conditions of γ-glutamyl transpeptidase from Bacillus licheniformis

Here, the crystallization and preliminary X-ray diffraction studies of Bacillus licheniformis γ-glutamyl transpeptidase (BlGT) are reported. The serendipitous finding of heterogeneous nucleants in the initial experiments provided the first crystallization conditions for the protein. Crystals were grown by hanging-drop vapour diffusion using a precipitant solution consisting of 20%(w/v) PEG 3350, 0.2 M magnesium chloride hexahydrate, 0.1 M Tris–HCl pH 8.2. The protein crystallized in the orthorhombic space group P2₁2₁2₁, with one heterodimer per asymmetric unit and unit-cell parameters a = 60.90, b = 61.97, c = 148.24 Å. The BlGT crystals diffracted to 2.95 Å resolution.