2fwp

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(New page: 200px<br /><applet load="2fwp" size="350" color="white" frame="true" align="right" spinBox="true" caption="2fwp, resolution 1.85&Aring;" /> '''Structure of PurE (N...)
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[[Image:2fwp.gif|left|200px]]<br /><applet load="2fwp" size="350" color="white" frame="true" align="right" spinBox="true"
 
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caption="2fwp, resolution 1.85&Aring;" />
 
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'''Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, bound to isocair'''<br />
 
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==Overview==
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==Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, bound to isocair==
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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 &gt; 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, --&gt; 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.
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<StructureSection load='2fwp' size='340' side='right'caption='[[2fwp]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[2fwp]] 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=2FWP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2FWP FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CIT:CITRIC+ACID'>CIT</scene>, <scene name='pdbligand=ICR:(4R)-5-IMINO-1-(5-O-PHOSPHONO-BETA-D-RIBOFURANOSYL)-4,5-DIHYDRO-1H-IMIDAZOLE-4-CARBOXYLIC+ACID'>ICR</scene></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2fwp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fwp OCA], [https://pdbe.org/2fwp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2fwp RCSB], [https://www.ebi.ac.uk/pdbsum/2fwp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2fwp ProSAT]</span></td></tr>
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</table>
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== Function ==
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[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]
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/fw/2fwp_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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/main_output.php?pdb_ID=2fwp ConSurf].
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<div style="clear:both"></div>
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<div style="background-color:#fffaf0;">
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== Publication Abstract from PubMed ==
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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 &gt; 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 --&gt; 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.
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==About this Structure==
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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<ref>PMID:16819818</ref>
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2FWP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Acetobacter_aceti Acetobacter aceti] with <scene name='pdbligand=ICR:'>ICR</scene> and <scene name='pdbligand=CIT:'>CIT</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FWP OCA].
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==Reference==
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16819818 16819818]
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</div>
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[[Category: Acetobacter aceti]]
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<div class="pdbe-citations 2fwp" style="background-color:#fffaf0;"></div>
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[[Category: Single protein]]
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[[Category: Kappock, T.J.]]
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[[Category: Starks, C.M.]]
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[[Category: CIT]]
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[[Category: ICR]]
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[[Category: acidophile]]
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[[Category: isocair]]
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[[Category: pure]]
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[[Category: purine biosynthesis]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jan 29 19:46:24 2008''
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==See Also==
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*[[Phosphoribosylaminoimidazole carboxylase 3D structures|Phosphoribosylaminoimidazole carboxylase 3D structures]]
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== References ==
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<references/>
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__TOC__
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</StructureSection>
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[[Category: Acetobacter aceti]]
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[[Category: Large Structures]]
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[[Category: Kappock TJ]]
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[[Category: Starks CM]]

Current revision

Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, bound to isocair

PDB ID 2fwp

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