Crystallization and preliminary X-ray diffraction analysis of aspartate aminotransferase from Saccharomyces cerevisiae.

Diffraction-quality crystals of S. cerevisiae cytoplasmic aspartate aminotransferase have been obtained by the hanging-drop vapor-diffusion method in the presence of pyridoxal phosphate and maleic acid, sodium acetate, ammonium acetate and polyethylene glycol. The crystals have the symmetry of the orthorhombic space groups P212121 or P21212 with unit-cell dimensions a = 130.2, b = 134.6 and c = 98.7 A. Square rod-shaped crystals with dimensions of approximately 0.2 x 0.2 x 0.5 mm diffract to spacings of 2 A. The calculated value of the Matthews coefficient, Vm = 2.4 A3 Da-1, is consistent with four subunits of aspartate aminotransferase per asymmetric unit.