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 g roup P2(1)2(1)2(1), with a = 51.84, b = 49.95, c = 34.96 Angstrom. Dif fractometer data were collected to 1.75 Angstrom. The structure was so lved by molecular replacement and refined to R = 0.168 for 7774 observ ed reflections [I greater than or equal to 2 sigma(I)] in the range 8. 0-1.75 Angstrom. In spite of the presence of EDTA, calcium ions are pr esent in both primary binding sites. As compared to the previously rep orted structures, the main differences concern the conformation of the N-terminal residues and the packing in the unit cell.