Structure of D-ribulose 5-phosphate 3-epimerase from Synechocystis to 1.6 A resolution.
The crystal structure of D-ribulose 5-phosphate 3-epimerase (RPE) from the cyanobacterium Synechocystis was determined by X-ray crystallography to 1.6 A resolution. The enzyme, which catalyzes the epimerization of D-ribulose 5-phosphate and D-xylulose 5-phosphate, assembles as a hexamer of (beta/alpha)(8)-barrels in the crystallographic asymmetric unit. The active site is highly similar to those of two previously reported RPEs and provides further evidence for essential catalytic roles for several active-site residues.