Crystallisation and preliminary crystallographic analysis of recombinant Xenopus laevis Cu,Zn superoxide dismutase b

The recombinant Cu,Zn superoxide dismutase from the South African frog Xenopus laevis, expressed in E. coli, has been crystallized in a form suitable for high resolution crystallographic investigations. The crystals grow from polyethylene glycol solutions, at pH 6.0, 28 degrees C, and belong to the orthorhombic space group P2(1)2(1)2(1) with unit cell edges a = 73.33, b = 68.86, c = 59.73 A, one protein dimer (32,000 M(r)) per asymmetric unit. Diffraction data have been collected to 3.0 A resolution, and a molecular replacement solution found for Xenopus laevis superoxide dismutase using the bovine enzyme as search model. The crystallographic R-factor corresponding to this solution is 0.412, in the 15.0-3.0 A resolution range.