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| | ==Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, at pH 8== | | ==Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, at pH 8== |
| - | <StructureSection load='2fw7' size='340' side='right' caption='[[2fw7]], [[Resolution|resolution]] 1.75Å' scene=''> | + | <StructureSection load='2fw7' size='340' side='right'caption='[[2fw7]], [[Resolution|resolution]] 1.75Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2fw7]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"acetimonas_aceti"_(pasteur_1864)_orla-jensen_1909 "acetimonas aceti" (pasteur 1864) orla-jensen 1909]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FW7 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2FW7 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2fw7]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Acetobacter_aceti Acetobacter aceti]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FW7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2FW7 FirstGlance]. <br> |
| - | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1u11|1u11]]</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]] 1.75Å</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=435 "Acetimonas aceti" (Pasteur 1864) Orla-Jensen 1909])</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=2fw7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fw7 OCA], [https://pdbe.org/2fw7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2fw7 RCSB], [https://www.ebi.ac.uk/pdbsum/2fw7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2fw7 ProSAT]</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=2fw7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fw7 OCA], [http://pdbe.org/2fw7 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2fw7 RCSB], [http://www.ebi.ac.uk/pdbsum/2fw7 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2fw7 ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/Q2QJL3_ACEAC Q2QJL3_ACEAC]] Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR) (By similarity).[PIRNR:PIRNR001338] | + | [https://www.uniprot.org/uniprot/Q2QJL3_ACEAC Q2QJL3_ACEAC] Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR) (By similarity).[PIRNR:PIRNR001338] |
| | == 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: Kappock, T J]] | + | [[Category: Acetobacter aceti]] |
| - | [[Category: Starks, C M]] | + | [[Category: Large Structures]] |
| - | [[Category: Acidophile]] | + | [[Category: Kappock TJ]] |
| - | [[Category: Lyase]] | + | [[Category: Starks CM]] |
| - | [[Category: Pure]]
| + | |
| - | [[Category: Purine biosynthesis]]
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| Structural highlights
Function
Q2QJL3_ACEAC Catalyzes the conversion of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR) (By similarity).[PIRNR:PIRNR001338]
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 (N5-CAIR) mutase (PurE) catalyzes the reversible interconversion of acid-labile compounds N5-CAIR and 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). We have examined PurE from the acidophilic bacterium Acetobacter aceti (AaPurE), focusing on its adaptation to acid pH and the roles of conserved residues His59 and His89. Both AaPurE and Escherichia coli PurE showed quasi-reversible acid-mediated inactivation, but wt AaPurE was much more stable at pH 3.5, with a > or = 20 degrees C higher thermal unfolding temperature at all pHs. His89 is not essential and does not function as part of a proton relay system. The kcat pH-rate profile was consistent with the assignment of pK1 to unproductive protonation of bound nucleotide and pK2 to deprotonation of His59. A 1.85 A resolution crystal structure of the inactive mutant H59N-AaPurE soaked in CAIR showed that protonation of CAIR C4 can occur in the absence of His59. The resulting species, modeled as isoCAIR [4(R)-carboxy-5-iminoimidazoline ribonucleotide], is strongly stabilized by extensive interactions with the enzyme and a water molecule. The carboxylate moiety is positioned in a small pocket proposed to facilitate nucleotide decarboxylation in the forward direction (N5-CAIR --> CAIR) [Meyer, E., Kappock, T. J., Osuji, C., and Stubbe, J. (1999) Biochemistry 38, 3012-3018]. Comparisons with model studies suggest that in the reverse (nonbiosynthetic) direction PurE favors protonation of CAIR C4. We suggest that the essential role of protonated His59 is to lower the barrier to decarboxylation by stabilizing a CO2-azaenolate intermediate.
Biochemical and structural studies of N5-carboxyaminoimidazole ribonucleotide mutase from the acidophilic bacterium Acetobacter aceti.,Constantine CZ, Starks CM, Mill CP, Ransome AE, Karpowicz SJ, Francois JA, Goodman RA, Kappock TJ Biochemistry. 2006 Jul 11;45(27):8193-208. PMID:16819818[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Constantine CZ, Starks CM, Mill CP, Ransome AE, Karpowicz SJ, Francois JA, Goodman RA, Kappock TJ. Biochemical and structural studies of N5-carboxyaminoimidazole ribonucleotide mutase from the acidophilic bacterium Acetobacter aceti. Biochemistry. 2006 Jul 11;45(27):8193-208. PMID:16819818 doi:http://dx.doi.org/10.1021/bi060465n
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