Purification, crystallization and preliminary crystallographic analysis of phosphoglucose isomerase from the hyperthermophilic archaeon Pyrococcus furiosus

The glycolytic enzyme phosphoglucose isomerase catalyses the reversible isomerization of glucose 6-phosphate to fructose 6-­phosphate. The phosphoglucose isomerase from the hyperthermophilic archaeon Pyrococcus furiosus, which shows no sequence similarity to any known bacterial or eukaryotic phosphoglucose isomerase, has been cloned and overexpressed in Escherichia coli, purified and subsequently crystallized by the hanging-drop method of vapour diffusion using 1.6 M sodium citrate as the precipitant at pH 6.5. Multiple-wavelength anomalous dispersive X-ray data have been collected to a maximum resolution of 1.92 Å on a single selenomethionine-incorporated crystal. This crystal belongs to space group C2, with approximate unit-cell parameters a = 84.7, b = 42.4, c = 57.3 Å, β = 120.6° and a monomer in the asymmetric unit.