View source for 1k97


==Crystal Structure of E. coli Argininosuccinate Synthetase in complex with Aspartate and Citrulline==
<StructureSection load='1k97' size='340' side='right'caption='[[1k97]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1k97]] 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=1K97 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K97 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&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ASP:ASPARTIC+ACID'>ASP</scene>, <scene name='pdbligand=CIR:CITRULLINE'>CIR</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=1k97 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k97 OCA], [https://pdbe.org/1k97 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k97 RCSB], [https://www.ebi.ac.uk/pdbsum/1k97 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k97 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ASSY_ECOLI ASSY_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/k9/1k97_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=1k97 ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: Argininosuccinate synthetase (AS) is the rate-limiting enzyme of both the urea and arginine-citrulline cycles. In mammals, deficiency of AS leads to citrullinemia, a debilitating and often fatal autosomal recessive urea cycle disorder, whereas its overexpression for sustained nitric oxide production via the arginine-citrulline cycle leads to the potentially fatal hypotension associated with septic and cytokine-induced circulatory shock. RESULTS: The crystal structure of E. coli AS (EAS) has been determined by the use of selenomethionine incorporation and MAD phasing. The structure has been refined at 1.6 A resolution in the absence of its substrates and at 2.0 A in the presence of aspartate and citrulline (EAS*CIT+ASP). Each monomer of this tetrameric protein has two structural domains: a nucleotide binding domain similar to that of the "N-type" ATP pyrophosphatase class of enzymes, and a novel catalytic/multimerization domain. The EAS*CIT+ASP structure clearly describes the binding of citrulline at the cleft between the two domains and of aspartate to a loop of the nucleotide binding domain, whereas homology modeling with the N-type ATP pyrophosphatases has provided the location of ATP binding. CONCLUSIONS: The first three-dimensional structures of AS are reported. The fold of the nucleotide binding domain confirms AS as the fourth structurally defined member of the N-type ATP pyrophosphatases. The structures identify catalytically important residues and suggest the requirement for a conformational change during the catalytic cycle. Sequence similarity between the bacterial and human enzymes has been used for providing insight into the structural and functional effects of observed clinical mutations.

The 1.6 A crystal structure of E. coli argininosuccinate synthetase suggests a conformational change during catalysis.,Lemke CT, Howell PL Structure. 2001 Dec;9(12):1153-64. PMID:11738042<ref>PMID:11738042</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1k97" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Howell PL]]
[[Category: Lemke CT]]