2.4.1.321 | structures of ligand-free and complex forms with cellobionic acid, gluconic acid, and a synthetic disaccharide product from glucuronic acid, up to 1.6 A resolution. The active site is located near the dimer interface. At subsite +1, the carboxylate group of gluconic acid and cellobionic acid is recognized by residues Arg609 and Lys613. Additionally, one residue from the neighboring protomer (Gln190) is involved. These residues are critical for the binding and catalysis of gluconic acid and glucuronic acid |