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[[Image:4eca.gif|left|200px]]<br />
<applet load="4eca" size="450" color="white" frame="true" align="right" spinBox="true"
caption="4eca, resolution 2.2&Aring;" />
'''ASPARAGINASE FROM E. COLI, MUTANT T89V WITH COVALENTLY BOUND ASPARTATE'''<br />


==Overview==
==ASPARAGINASE FROM E. COLI, MUTANT T89V WITH COVALENTLY BOUND ASPARTATE==
Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine, to L-aspartate via a threonine-bound acyl-enzyme intermediate. A nearly, inactive mutant in which one of the active site threonines, Thr-89, was, replaced by valine was constructed, expressed, and crystallized. Its, structure, solved at 2.2 A resolution, shows high overall similarity to, the wild-type enzyme, but an aspartyl moiety is covalently bound to, Thr-12, resembling a reaction intermediate. Kinetic analysis confirms the, deacylation deficiency, which is also explained on a structural basis. The, previously identified oxyanion hole is described in more detail.
<StructureSection load='4eca' size='340' side='right'caption='[[4eca]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4eca]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4ECA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4ECA 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=AEI:THREONINE-ASPARTIC+ESTER'>AEI</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=4eca FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4eca OCA], [https://pdbe.org/4eca PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4eca RCSB], [https://www.ebi.ac.uk/pdbsum/4eca PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4eca ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ASPG2_ECOLI ASPG2_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/ec/4eca_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=4eca ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine to L-aspartate via a threonine-bound acyl-enzyme intermediate. A nearly inactive mutant in which one of the active site threonines, Thr-89, was replaced by valine was constructed, expressed, and crystallized. Its structure, solved at 2.2 A resolution, shows high overall similarity to the wild-type enzyme, but an aspartyl moiety is covalently bound to Thr-12, resembling a reaction intermediate. Kinetic analysis confirms the deacylation deficiency, which is also explained on a structural basis. The previously identified oxyanion hole is described in more detail.


==About this Structure==
A covalently bound catalytic intermediate in Escherichia coli asparaginase: crystal structure of a Thr-89-Val mutant.,Palm GJ, Lubkowski J, Derst C, Schleper S, Rohm KH, Wlodawer A FEBS Lett. 1996 Jul 22;390(2):211-6. PMID:8706862<ref>PMID:8706862</ref>
4ECA is a [[http://en.wikipedia.org/wiki/Single_protein Single protein]] structure of sequence from [[http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]]. Active as [[http://en.wikipedia.org/wiki/Hydrolase Hydrolase]], with EC number [[http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.1 3.5.1.1]]. Structure known Active Sites: AS, BS, CS and DS. Full crystallographic information is available from [[http://ispc.weizmann.ac.il/oca-bin/ocashort?id=4ECA OCA]].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
A covalently bound catalytic intermediate in Escherichia coli asparaginase: crystal structure of a Thr-89-Val mutant., Palm GJ, Lubkowski J, Derst C, Schleper S, Rohm KH, Wlodawer A, FEBS Lett. 1996 Jul 22;390(2):211-6. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8706862 8706862]
</div>
[[Category: Escherichia coli]]
<div class="pdbe-citations 4eca" style="background-color:#fffaf0;"></div>
[[Category: Single protein]]
[[Category: Lubkowski, J.]]
[[Category: Palm, G.J.]]
[[Category: Wlodawer, A.]]
[[Category: acyl-enzyme intermediate]]
[[Category: hydrolase]]
[[Category: threonine amidohydrolase]]


''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Oct 30 08:38:20 2007''
==See Also==
*[[Asparaginase 3D structures|Asparaginase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Lubkowski J]]
[[Category: Palm GJ]]
[[Category: Wlodawer A]]