1q3n

Crystal structure of KDO8P synthase in its binary complex with substrate PEP

spinqualitylabelsall models 1q3n, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1q3n is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.7Å Ligands: PEP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KDSA_ECOLI Synthesis of KDO 8-P which is required for lipid A maturation and cellular growth.[HAMAP-Rule:MF_00056] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The enzyme 3-deoxy-D-manno-2-octulosonate-8-phosphate synthase (KDO8PS) catalyses the condensation of arabinose 5-phosphate (A5P) and phosphoenol pyruvate (PEP) to obtain 3-deoxy-D-manno-2-octulosonate-8-phosphate (KDO8P). We have elucidated initial modes of ligand binding in KDO8PS binary complexes by X-ray crystallography. Structures of the apo-enzyme and of binary complexes with the substrate PEP, the product KDO8P and the catalytically inactive 1-deoxy analog of arabinose 5-phosphate (1dA5P) were obtained. The KDO8PS active site resembles an irregular funnel with positive electrostatic potential situated at the bottom of the PEP-binding sub-site, which is the primary attractive force towards negatively charged phosphate moieties of all ligands. The structures of the ligand-free apo-KDO8PS and the binary complex with the product KDO8P visualize for the first time the role of His202 as an active-site gate. Examination of the crystal structures of KDO8PS with the KDO8P or 1dA5P shows these ligands bound to the enzyme in the PEP-binding sub-site, and not as expected to the A5P sub-site. Taken together, the structures presented here strengthen earlier evidence that this enzyme functions predominantly through positional catalysis, map out the roles of active-site residues and provide evidence that explains the total lack of catalytic reversibility. Crystal structures of Escherichia coli KDO8P synthase complexes reveal the source of catalytic irreversibility.,Vainer R, Belakhov V, Rabkin E, Baasov T, Adir N J Mol Biol. 2005 Aug 19;351(3):641-52. PMID:16023668 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Kdo-8-phosphate synthase

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