A thermostable xylose isomerase from Thermus thermophilus: Biochemical characterization, crystallization, and preliminary X-ray analyses

A highly thermostable xq lose isomerase from Thermus thermophilus has been expressed in Escherichia coli and crystallized, The purified enzyme shows its optimum temperature at 90 degrees C. It has been crystallized at room temperature using polyethylene glycol 4000 as the precipitant. The crystal belongs to the orthorhombic space group P2(1)2(1)2(1), with unit cell parameters of a = 73,34 Angstrom, b = 144.05 Angstrom, 155.07 Angstrom. The presence of one molecule of tetrameric xylose isomerase in the asymmetric unit gives a crystal volume per protein mass (V-m) of 2.32 Angstrom(3)/Da and the solvent content of 47.0% by volume. The diffraction pattern extends to 1.9 Angstrom Bragg spacing with synchrotron radiation and a set of native data has been collected to 2.3 Angstrom.