1qcz

<StructureSection load='1qcz' size='340' side='right' caption='[[1qcz]], [[Resolution|resolution]] 1.50&Aring;' scene=''>

<table><tr><td colspan='2'>[[1qcz]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QCZ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1QCZ FirstGlance]. <br>

</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Phosphoribosylaminoimidazole_carboxylase Phosphoribosylaminoimidazole carboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.1.21 4.1.1.21] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1qcz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qcz OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1qcz RCSB], [http://www.ebi.ac.uk/pdbsum/1qcz PDBsum]</span></td></tr>

[[http://www.uniprot.org/uniprot/PUR6_ECOLI PUR6_ECOLI]] Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR).

<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/qc/1qcz_consurf.spt"</scriptWhenChecked>

</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].

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== 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<ref>PMID:10574791</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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*[[Phosphoribosylaminoimidazole carboxylase|Phosphoribosylaminoimidazole carboxylase]]

[[Category: Phosphoribosylaminoimidazole carboxylase]]

[[Category: Ealick, S E]]

[[Category: Mathews, I I]]

[[Category: Lyase]]