Overexpression, crystallization and preliminary X-ray diffraction analysis of L-ribose isomerase from Acinetobacter sp. strain DL-28.

Acinetobacter sp. L-ribose isomerase (L-RI) catalyzes a reversible isomerization reaction between L-ribose and L-ribulose. To date, information on L-RI remains limited and its amino-acid sequence shows no similarity to those of any known enzymes. Here, recombinant His-tagged L-RI was successfully overexpressed, purified and crystallized. Crystals of His-tagged L-RI were obtained by the hanging-drop vapour-diffusion method at room temperature as two crystal forms which belonged to the monoclinic space group C2, with unit-cell parameters a = 96.60, b = 105.89, c = 71.83 Å, β = 118.16°, and the orthorhombic space group F222, with unit-cell parameters a = 96.44, b = 106.26, c = 117.83 Å. Diffraction data were collected to 3.1 and 2.2 Å resolution, respectively.