W. Liu et al., Overexpression, purification, crystallization and preliminary X-ray diffraction analysis of Cu,Zn superoxide dismutase from Peking duck, ACT CRYST D, 57, 2001, pp. 1646-1649
The cDNA encoding Peking duck Cu,Zn superoxide dismutase (dSOD) was cloned
and sequenced. The recombinant enzyme was overexpressed in Escherichia coli
, purified to homogeneity and crystallized using the sitting-drop vapour-di
ffusion technique. Trigonal crystals of dSOD were obtained at 278 K at low
ionic strength and around neutral pH. These crystals belong to space group
P3(2)21, with unit-cell parameters a = 124.4, c = 163.5 Angstrom, gamma = 1
20 degrees. The asymmetric unit contains four dimers (eight monomers of Cu,
Zn dSOD) and has a 56% solvent content, with a V-M of 2.8 Angstrom (3) Da(-
1). On a Rigaku R-AXIS IIc image-plate area-detector system, the crystal di
ffracted to 2.9 Angstrom. Unusual supermolecular double-helix packing with
9(2)2 non-crystallographic symmetry in crystals has been observed in the in
itial structural analysis.