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

Abstract

A highly thermostable xylose isomerase from Thermus thermophilus has been expressed in Escherichia coli and crystallized. The purified enzyme shows its optimum temperature at 90°C. It has been crystallized at room temperature using polyethylene glycol 4000 as the precipitant. The crystal belongs to the orthorhombic space group P212121, with unit cell parameters of a = 73.34 ?, b = 144.05 ?, c = 155.07 ?. The presence of one molecule of tetrameric xylose isomerase in the asymmetric unit gives a crystal volume per protein mass (Vm) of 2.32 ?3/Da and the solvent content of 47.0% by volume. The diffraction pattern extends to 1.9 ? Bragg spacing with synchrotron radiation and a set of native data has been collected to 2.3 ?.