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[[Image:2qgf.jpg|left|200px]]
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{{STRUCTURE_2qgf|  PDB=2qgf  |  SCENE=  }}
'''Structure of regulatory chain mutant H20A of asparate transcarbamoylase from E. coli'''


==Structure of regulatory chain mutant H20A of asparate transcarbamoylase from E. coli==
<StructureSection load='2qgf' size='340' side='right'caption='[[2qgf]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2qgf]] is a 4 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=2QGF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2QGF FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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=2qgf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qgf OCA], [https://pdbe.org/2qgf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2qgf RCSB], [https://www.ebi.ac.uk/pdbsum/2qgf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2qgf ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PYRB_ECOLI PYRB_ECOLI]
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/qg/2qgf_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</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=2qgf ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Asp19 and His20 of Escherichia coli aspartate transcarbamoylase (EC 2.1.3.2) function in the binding of the triphosphate and ribose moieties of ATP and CTP and thereby may mediate important heterotropic regulation. The roles of these residues were investigated by individually mutating each of them to alanine and determining both the kinetic parameters and the structures of the mutant enzymes. The structures were determined by X-ray crystallography at 2.15 and 2.75 A resolution for His20Ar and Asp19Ar, respectively. Analysis was carried out on the unliganded T-state form. The structures of the mutants did not show gross structural divergence from the canonical T-state, but showed small and systematic differences that were analyzed by global conformational analysis. Structural analysis and comparison with other regulatory-chain mutants confirmed that the Asp19Ar mutant represents the stabilized T-state, while structural analysis of the His20Ar form indicated that it represents an equilibrium shifted towards the R-state. Global analysis of the Asp19Ar and His20Ar enzymes suggested a possible role as molecular modulators of the heterotropic effects caused by the binding of nucleotides at the regulatory site. These studies highlighted the structural determinants of T- or R-state stabilization. Additionally, application of the ;consensus modeling' methodology combined with high-resolution data allowed the determination of unclear structural features contributing to nucleotide specificity and the role of the N-termini of the regulatory chains.


==Overview==
Comparison of two T-state structures of regulatory-chain mutants of Escherichia coli aspartate transcarbamoylase suggests that His20 and Asp19 modulate the response to heterotropic effectors.,Stec B, Williams MK, Stieglitz KA, Kantrowitz ER Acta Crystallogr D Biol Crystallogr. 2007 Dec;63(Pt 12):1243-53. Epub 2007, Nov 16. PMID:18084072<ref>PMID:18084072</ref>
Asp19 and His20 of Escherichia coli aspartate transcarbamoylase (EC 2.1.3.2) function in the binding of the triphosphate and ribose moieties of ATP and CTP and thereby may mediate important heterotropic regulation. The roles of these residues were investigated by individually mutating each of them to alanine and determining both the kinetic parameters and the structures of the mutant enzymes. The structures were determined by X-ray crystallography at 2.15 and 2.75 A resolution for His20Ar and Asp19Ar, respectively. Analysis was carried out on the unliganded T-state form. The structures of the mutants did not show gross structural divergence from the canonical T-state, but showed small and systematic differences that were analyzed by global conformational analysis. Structural analysis and comparison with other regulatory-chain mutants confirmed that the Asp19Ar mutant represents the stabilized T-state, while structural analysis of the His20Ar form indicated that it represents an equilibrium shifted towards the R-state. Global analysis of the Asp19Ar and His20Ar enzymes suggested a possible role as molecular modulators of the heterotropic effects caused by the binding of nucleotides at the regulatory site. These studies highlighted the structural determinants of T- or R-state stabilization. Additionally, application of the ;consensus modeling' methodology combined with high-resolution data allowed the determination of unclear structural features contributing to nucleotide specificity and the role of the N-termini of the regulatory chains.


==About this Structure==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
2QGF is a [[Protein complex]] structure of sequences 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=2QGF OCA].
</div>
<div class="pdbe-citations 2qgf" style="background-color:#fffaf0;"></div>


==Reference==
==See Also==
Comparison of two T-state structures of regulatory-chain mutants of Escherichia coli aspartate transcarbamoylase suggests that His20 and Asp19 modulate the response to heterotropic effectors., Stec B, Williams MK, Stieglitz KA, Kantrowitz ER, Acta Crystallogr D Biol Crystallogr. 2007 Dec;63(Pt 12):1243-53. Epub 2007, Nov 16. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18084072 18084072]
*[[Aspartate carbamoyltransferase 3D structures|Aspartate carbamoyltransferase 3D structures]]
[[Category: Aspartate carbamoyltransferase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Protein complex]]
[[Category: Large Structures]]
[[Category: Kantrowitz, E R.]]
[[Category: Kantrowitz ER]]
[[Category: Stec, B.]]
[[Category: Stec B]]
[[Category: Stieglitz, K A.]]
[[Category: Stieglitz KA]]
[[Category: Williams, M K.]]
[[Category: Williams MK]]
[[Category: Allosteric enzyme regulatory chain mutation]]
[[Category: Heterotropic regulation]]
[[Category: Transferase/transferase regulator complex]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 14:55:00 2008''