Crystallization and preliminary X-ray diffraction analysis of phosphoglucose/phosphomannose isomerase from Pyrobaculum aerophilum

Phosphoglucose isomerase from the crenarchaeon Pyrobaculum aerophilum (PaPGI/PMI) shows virtually no sequence similarity to its counterparts from bacterial and eukaryotic sources and belongs to a unique group within the PGI superfamily. Whereas conventional PGIs show strict substrate specificity for glucose 6-phosphate and fructose 6-phosphate, PaPGI/PMI can also catalyse the isomerization of mannose 6-phosphate. In order to establish its relatedness within the PGI family and to elucidate the structural basis for its broader specificity, this enzyme was crystallized. The crystals belong to space group P2(1) and a complete data set extending to 1.6 Angstrom resolution has been collected.