Crystallization and preliminary X‐ray diffraction studies of l‐rhamnose isomerase from Pseudomonas stutzeri

l-Rhamnose isomerase from Pseudomonas stutzeri (P. stutzeri l-RhI) catalyzes not only the reversible isomerization of l-rhamnose to l-rhamnulose, but also isomerization between various rare aldoses and ketoses. Purified His-tagged P. stutzeri l-RhI was crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 74.3, b = 104.0, c = 107.0 A, β = 106.8°. Diffraction data have been collected to 2.0 A resolution. The molecular weight of the purified P. stutzeri l-RhI with a His tag at the C-terminus was confirmed to be 47.7 kDa by MALDI–TOF mass-spectrometric analysis and the asymmetric unit is expected to contain four molecules.