View source for 3c20


==Crystal Structure of Threonine-sensitive Aspartokinase from Methanococcus jannaschii with L-aspartate==
<StructureSection load='3c20' size='340' side='right'caption='[[3c20]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3c20]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3C20 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3C20 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]] 2.7&#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=FMT:FORMIC+ACID'>FMT</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=3c20 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3c20 OCA], [https://pdbe.org/3c20 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3c20 RCSB], [https://www.ebi.ac.uk/pdbsum/3c20 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3c20 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AK_METJA AK_METJA] 
== 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/c2/3c20_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=3c20 ConSurf].
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== Publication Abstract from PubMed ==
The commitment step to the aspartate pathway of amino acid biosynthesis is the phosphorylation of aspartic acid catalyzed by aspartokinase (AK). Most microorganisms and plants have multiple forms of this enzyme, and many of these isofunctional enzymes are subject to feedback regulation by the end products of the pathway. However, the archeal species Methanococcus jannaschii has only a single, monofunctional form of AK. The substrate l-aspartate binds to this recombinant enzyme in two different orientations, providing the first structural evidence supporting the relaxed regiospecificity previously observed with several alternative substrates of Escherichia coli AK ( Angeles, T. S., Hunsley, J. R., and Viola, R. E. (1992) Biochemistry 31, 799-805 ). Binding of the nucleotide substrate triggers significant domain movements that result in a more compact quaternary structure. In contrast, the highly cooperative binding of the allosteric regulator l-threonine to multiple sites on this dimer of dimers leads to an open enzyme structure. A comparison of these structures supports a mechanism for allosteric regulation in which the domain movements induced by threonine binding causes displacement of the substrates from the enzyme, resulting in a relaxed, inactive conformation.

The structural basis for allosteric inhibition of a threonine-sensitive aspartokinase.,Liu X, Pavlovsky AG, Viola RE J Biol Chem. 2008 Jun 6;283(23):16216-25. Epub 2008 Mar 11. PMID:18334478<ref>PMID:18334478</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 3c20" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Methanocaldococcus jannaschii]]
[[Category: Liu X]]
[[Category: Pavlovsky AG]]
[[Category: Viola RE]]