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| | ==E. coli PurE H45Q mutant complexed with CAIR== | | ==E. coli PurE H45Q mutant complexed with CAIR== |
| - | <StructureSection load='2nsj' size='340' side='right' caption='[[2nsj]], [[Resolution|resolution]] 2.31Å' scene=''> | + | <StructureSection load='2nsj' size='340' side='right'caption='[[2nsj]], [[Resolution|resolution]] 2.31Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2nsj]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NSJ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2NSJ FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2nsj]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NSJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2NSJ FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=C2R:5-AMINO-1-(5-O-PHOSPHONO-BETA-D-RIBOFURANOSYL)-1H-IMIDAZOLE-4-CARBOXYLIC+ACID'>C2R</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.31Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2ate|2ate]], [[2nsh|2nsh]], [[2nsl|2nsl]]</td></tr>
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=C2R:5-AMINO-1-(5-O-PHOSPHONO-BETA-D-RIBOFURANOSYL)-1H-IMIDAZOLE-4-CARBOXYLIC+ACID'>C2R</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">purE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2nsj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2nsj OCA], [https://pdbe.org/2nsj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2nsj RCSB], [https://www.ebi.ac.uk/pdbsum/2nsj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2nsj ProSAT]</span></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>
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| - | <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=2nsj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2nsj OCA], [http://pdbe.org/2nsj PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2nsj RCSB], [http://www.ebi.ac.uk/pdbsum/2nsj PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2nsj ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/PURE_ECOLI PURE_ECOLI]] Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). | + | [https://www.uniprot.org/uniprot/PURE_ECOLI PURE_ECOLI] Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | ==See Also== | | ==See Also== |
| - | *[[Phosphoribosylaminoimidazole carboxylase|Phosphoribosylaminoimidazole carboxylase]] | + | *[[Phosphoribosylaminoimidazole carboxylase 3D structures|Phosphoribosylaminoimidazole carboxylase 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Bacillus coli migula 1895]] | + | [[Category: Escherichia coli]] |
| - | [[Category: Phosphoribosylaminoimidazole carboxylase]] | + | [[Category: Large Structures]] |
| - | [[Category: Ealick, S E]] | + | [[Category: Ealick SE]] |
| - | [[Category: Morar, M]] | + | [[Category: Morar M]] |
| - | [[Category: Central three-layer alpha-beta-alpha sandwich]]
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| - | [[Category: Kinked c-terminal helix]]
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| - | [[Category: Lyase]]
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| Structural highlights
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
N5-Carboxyaminoimidazole ribonucleotide mutase (N5-CAIR mutase or PurE) from Escherichia coli catalyzes the reversible interconversion of N5-CAIR to carboxyaminoimidazole ribonucleotide (CAIR) with direct CO2 transfer. Site-directed mutagenesis, a pH-rate profile, DFT calculations, and X-ray crystallography together provide new insight into the mechanism of this unusual transformation. These studies suggest that a conserved, protonated histidine (His45) plays an essential role in catalysis. The importance of proton transfers is supported by DFT calculations on CAIR and N5-CAIR analogues in which the ribose 5'-phosphate is replaced with a methyl group. The calculations suggest that the nonaromatic tautomer of CAIR (isoCAIR) is only 3.1 kcal/mol higher in energy than its aromatic counterpart, implicating this species as a potential intermediate in the PurE-catalyzed reaction. A structure of wild-type PurE cocrystallized with 4-nitroaminoimidazole ribonucleotide (NO2-AIR, a CAIR analogue) and structures of H45N and H45Q PurEs soaked with CAIR have been determined and provide the first insight into the binding of an intact PurE substrate. A comparison of 19 available structures of PurE and PurE mutants in apo and nucleotide-bound forms reveals a common, buried carboxylate or CO2 binding site for CAIR and N5-CAIR in a hydrophobic pocket in which the carboxylate or CO2 interacts with backbone amides. This work has led to a mechanistic proposal in which the carboxylate orients the substrate for proton transfer from His45 to N5-CAIR to form an enzyme-bound aminoimidazole ribonucleotide (AIR) and CO2 intermediate. Subsequent movement of the aminoimidazole moiety of AIR reorients it for addition of CO2 at C4 to generate isoCAIR. His45 is now in a position to remove a C4 proton to produce CAIR.
N5-CAIR mutase: role of a CO2 binding site and substrate movement in catalysis.,Hoskins AA, Morar M, Kappock TJ, Mathews II, Zaugg JB, Barder TE, Peng P, Okamoto A, Ealick SE, Stubbe J Biochemistry. 2007 Mar 13;46(10):2842-55. Epub 2007 Feb 14. PMID:17298082[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hoskins AA, Morar M, Kappock TJ, Mathews II, Zaugg JB, Barder TE, Peng P, Okamoto A, Ealick SE, Stubbe J. N5-CAIR mutase: role of a CO2 binding site and substrate movement in catalysis. Biochemistry. 2007 Mar 13;46(10):2842-55. Epub 2007 Feb 14. PMID:17298082 doi:http://dx.doi.org/10.1021/bi602436g
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