CRYSTALLIZATION AND PRELIMINARY-X-RAY CRYSTALLOGRAPHIC STUDIES ON TYPE-III ANTIFREEZE PROTEIN

Type III antifreeze protein, more specifically the recombinant QAE-Sep hadex-binding isoform, has been crystalized in 50-55% saturated ammoni um sulfate, 0.1 M sodium acetate, pH 4.0-4.5. The resultant crystals b elong to the orthorhombic space group P2(1)2(1)2(1) with a = 32.60 Ang strom, b = 39.00 Angstrom, and c = 46.57 Angstrom and diffract to at l east 1.7 Angstrom. A set of 1.7-Angstrom native data has been collecte d, with completeness 93.4% and R(sym) of 0.069. Initial screening for heavy-atom derivatives has yielded a Pt-bound derivative.