1qcz

CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY

spinqualitylabelsall models 1qcz, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qcz 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 1.5Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PURE_ECOLI Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). 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 BACKGROUND: Conversion of 5-aminoimidazole ribonucleotide (AIR) to 4-carboxyaminoimidazole ribonucleotide (CAIR) in Escherichia coli requires two proteins - PurK and PurE. PurE has recently been shown to be a mutase that catalyzes the unusual rearrangement of N(5)-carboxyaminoimidazole ribonucleotide (N(5)-CAIR), the PurK reaction product, to CAIR. PurEs from higher eukaryotes are homologous to E. coli PurE, but use AIR and CO(2) as substrates to produce CAIR directly. RESULTS: The 1.50 A crystal structure of PurE reveals an octameric structure with 422 symmetry. A central three-layer (alphabetaalpha) sandwich domain and a kinked C-terminal helix form the folded structure of the monomeric unit. The structure reveals a cleft at the interface of two subunits and near the C-terminal helix of a third subunit. Co-crystallization experiments with CAIR confirm this to be the mononucleotide-binding site. The nucleotide is bound predominantly to one subunit, with conserved residues from a second subunit making up one wall of the cleft. CONCLUSIONS: The crystal structure of PurE reveals a unique quaternary structure that confirms the octameric nature of the enzyme. An analysis of the native crystal structure, in conjunction with sequence alignments and studies of co-crystals of PurE with CAIR, reveals the location of the active site. The environment of the active site and the analysis of conserved residues between the two classes of PurEs suggests a model for the differences in their substrate specificities and the relationship between their mechanisms. Crystal structure of Escherichia coli PurE, an unusual mutase in the purine biosynthetic pathway.,Mathews II, Kappock TJ, Stubbe J, Ealick SE Structure. 1999 Nov 15;7(11):1395-406. PMID:10574791 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoribosylaminoimidazole carboxylase 3D structures

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