View source for 2wkv


==BIOSYNTHETIC THIOLASE FROM Z. RAMIGERA. COMPLEX OF THE N316D MUTANT WITH COENZYME A.==
<StructureSection load='2wkv' size='340' side='right'caption='[[2wkv]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2wkv]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Zoogloea_ramigera Zoogloea ramigera]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2WKV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2WKV 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=COA:COENZYME+A'>COA</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=2wkv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2wkv OCA], [https://pdbe.org/2wkv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2wkv RCSB], [https://www.ebi.ac.uk/pdbsum/2wkv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2wkv ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/THIL_SHIZO THIL_SHIZO] 
== 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/wk/2wkv_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=2wkv ConSurf].
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== Publication Abstract from PubMed ==
The biosynthetic thiolase catalyzes a Claisen condensation reaction between acetyl-CoA and the enzyme acetylated at Cys89. Two oxyanion holes facilitate this catalysis: oxyanion hole I stabilizes the enolate intermediate generated from acetyl-CoA, whereas oxyanion hole II stabilizes the tetrahedral intermediate of the acetylated enzyme. The latter intermediate is formed when the alpha-carbanion of acetyl-CoA enolate reacts with the carbonyl carbon of acetyl-Cys89, after which C-C bond formation is completed. Oxyanion hole II is made of two main chain peptide NH groups, whereas oxyanion hole I is formed by a water molecule (Wat82) and NE2(His348). Wat82 is anchored in the active site by an optimal set of hydrogen bonding interactions, including a hydrogen bond to ND2(Asn316). Here, the importance of Asn316 and His348 for catalysis has been studied; in particular, the properties of the N316D, N316A, N316H, H348A, and H348N variants have been determined. For the N316D variant, no activity could be detected. For each of the remaining variants, the kcat/Km value for the Claisen condensation catalysis is reduced by a factor of several hundred, whereas the thiolytic degradation catalysis is much less affected. The crystal structures of the variants show that the structural changes in the active site are minimal. Our studies confirm that oxyanion hole I is critically important for the condensation catalysis. Removing either one of the hydrogen bond donors causes the loss of at least 3.4 kcal/mol of transition state stabilization. It appears that in the thiolytic degradation direction, oxyanion hole I is not involved in stabilizing the transition state of its rate limiting step. However, His348 has a dual role in the catalytic cycle, contributing to oxyanion hole I and activating Cys89. The analysis of the hydrogen bonding interactions in the very polar catalytic cavity shows the importance of two conserved water molecules, Wat82 and Wat49, for the formation of oxyanion hole I and for influencing the reactivity of the catalytic base, Cys378, respectively. Cys89, Asn316, and His348 form the CNH-catalytic triad of the thiolase superfamily. Our findings are also discussed in the context of the importance of this triad for the catalytic mechanism of other enzymes of the thiolase superfamily.

The thiolase reaction mechanism: the importance of Asn316 and His348 for stabilizing the enolate intermediate of the Claisen condensation.,Merilainen G, Poikela VM, Kursula P, Wierenga RK Biochemistry. 2009 Oct 20. PMID:19842716<ref>PMID:19842716</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 2wkv" style="background-color:#fffaf0;"></div>

==See Also==
*[[Thiolase 3D structures|Thiolase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Zoogloea ramigera]]
[[Category: Kursula P]]
[[Category: Merilainen G]]
[[Category: Poikela V]]
[[Category: Wierenga RK]]