CRYSTALLIZATION AND PRELIMINARY-X-RAY CHARACTERIZATION OF ASPARTATE-AMINOTRANSFERASE FROM AN EXTREME THERMOPHILE, THERMUS-THERMOPHILUS HB8

Recombinant aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8, has been crystallized in two diff erent crystal forms. The crystals of both forms are orthorhombic and b elong to space group P2(1)2(1)2(1) with cell dimensions a = 124.3, b = 113.6 and c = 61.6 Angstrom for form I and a = 197.3, b = 109.7 and c = 80.3 Angstrom for form II. The crystals of form I and II diffract t o 2.1 and 2.5 Angstrom resolution, respectively, on a conventional lab oratory rotating-anode source. Two heavy-atom derivatives have been id entified for Form I.