title: X-ray crystal structure of D-xylose isomerase at 4-A resolution.
abstract: The structure of D-xylose isomerase from Streptomyces rubiginosus has been determined at 4-A resolution using multiple isomorphous phasing techniques. The folding of the polypeptide chain has been established and consists of two structural domains. The larger domain consists of eight beta-strand alpha-helix (beta alpha) units arranged in a configuration similar to that found for triose phosphate isomerase, 2-keto-3-deoxy-6-phosphogluconate aldolase, and pyruvate kinase. The smaller domain forms a loop away from the larger domain but overlapping the larger domain of another subunit so that a tightly bound dimer is formed. The tetramer then consists of two such dimers. The location of the active site in the enzyme has been tentatively identified from studies using a crystal grown from a solution containing the inhibitor xylitol.
mesh_terms: D019747:Aldose-Ketose Isomerases; D002238:Carbohydrate Epimerases / Q000302:isolation & purification*; D003460:Crystallization; D046911:Macromolecular Substances; D008958:Models, Molecular; D011487:Protein Conformation; D013302:Streptomyces / Q000201:enzymology*; D014961:X-Ray Diffraction
chemical_list: D046911:Macromolecular Substances; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase