Crystallization and preliminary X-ray analysis of 5′-methylthioribose kinase from Bacillus subtilis and Arabidopsis thaliana

Recombinant Bacillus subtilis 5′-methylthioribose (MTR) kinase has been expressed, purified and subsequently crystallized using the hanging-drop vapor-diffusion technique. With PEG 2000MME as the precipitant, two different crystal forms have been grown in the absence and presence of the detergent CHAPS. These crystals belong to space groups P2₁2₁2 ₁ (unit-cell parameters a = 193.7, b = 83.2, c = 51.6 Å) and P2₁2₁2 (unit-cell parameters a = 213.8, b = 83.2, c = 51.5 Å), respectively. The crystals grown in the presence of CHAPS diffract to 2.2 Å resolution at Station X8C, National Synchrotron Light Source (NSLS). For both crystal forms, the presence of two monomers per asymmetric unit is predicted (Matthews coefficient V_M = 2.29 and 2.52 ų Da^-1, respectively). Recombinant C-terminally histidine-tagged Arabidopsis thaliana MTR kinase has also been expressed, purified and refolded into its active form. Rod-shaped crystals of this protein were grown from PEG 8000 using the hanging-drop vapor-diffusion technique. These crystals exhibit the symmetry of space group C₂ (unit-cell parameters a = 162.3, b = 83.3, c = 91.0 Å, β = 117.8°) and diffract to 1.9 Å resolution at Station X8C, NSLS. Two monomers are estimated to be present in the asymmetric unit (V_M = 2.82 ų Da^-1).