X-ray structure of a new crystal form of pike 4.10 beta parvalbumin.

A new crystal form of pike (pI 4.10) parvalbumin has been crystallized in presence of EDTA at pH 8.0. The crystals are orthorhombic, space group P2(1)2(1)2(1), with a = 51.84, b = 49.95, c = 34.96 A. Diffractometer data were collected to 1.75 A. The structure was solved by molecular replacement and refined to R = 0.168 for 7774 observed reflections [I>/= 2sigma(I)] in the range 8.0-1.75 A. In spite of the presence of EDTA, calcium ions are present in both primary binding sites. As compared to the previously reported structures, the main differences concern the conformation of the N-terminal residues and the packing in the unit cell.