4qee

Room temperature X-ray structure of D-xylose isomerase in complex with two Ni2+ ions and L-ribose

spinqualitylabelsall models 4qee, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4qee is a 1 chain structure with sequence from Streptomyces rubiginosus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NI, Z6J Related: 4qdp, 4qdw, 4qe1, 4qe4, 4qe5, 4qeh Activity: Xylose isomerase, with EC number 5.3.1.5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [XYLA_STRRU] Involved in D-xylose catabolism. Publication Abstract from PubMed D-xylose isomerase (XI) is capable of sugar isomerization and slow conversion of some monosaccharides into their C2-epimers. We present X-ray and neutron crystallographic studies to locate H and D atoms during the respective isomerization and epimerization of L-arabinose to L-ribulose and L-ribose, respectively. Neutron structures in complex with cyclic and linear L-arabinose have demonstrated that the mechanism of ring-opening is the same as for the reaction with D-xylose. Structural evidence and QM/MM calculations show that in the reactive Michaelis complex L-arabinose is distorted to the high-energy 5S1 conformation; this may explain the apparent high KM for this sugar. MD-FEP simulations indicate that amino acid substitutions in a hydrophobic pocket near C5 of L-arabinose can enhance sugar binding. L-ribulose and L-ribose were found in furanose forms when bound to XI. We propose that these complexes containing Ni2+ cofactors are Michaelis-like and the isomerization between these two sugars proceeds via a cis-ene-diol mechanism. L-Arabinose Binding, Isomerization, and Epimerization by D-Xylose Isomerase: X-Ray/Neutron Crystallographic and Molecular Simulation Study.,Langan P, Sangha AK, Wymore T, Parks JM, Yang ZK, Hanson BL, Fisher Z, Mason SA, Blakeley MP, Forsyth VT, Glusker JP, Carrell HL, Smith JC, Keen DA, Graham DE, Kovalevsky A Structure. 2014 Aug 12. pii: S0969-2126(14)00210-X. doi:, 10.1016/j.str.2014.07.002. PMID:25132082 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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