View source for 2vzk


==Structure of the acyl-enzyme complex of an N-terminal nucleophile (Ntn) hydrolase, OAT2==
<StructureSection load='2vzk' size='340' side='right'caption='[[2vzk]], [[Resolution|resolution]] 2.33&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2vzk]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_clavuligerus Streptomyces clavuligerus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2VZK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2VZK 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]] 2.33&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=TH5:O-ACETYL-L-THREONINE'>TH5</scene>, <scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</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=2vzk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2vzk OCA], [https://pdbe.org/2vzk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2vzk RCSB], [https://www.ebi.ac.uk/pdbsum/2vzk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2vzk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GNAT2_STRCL GNAT2_STRCL] Catalyzes the biosynthesis of ornithine by transacetylation between N(2)-acetylornithine and glutamate. It can also use L-arginine, L-glutamine and L-lysine as acetyl acceptors.<ref>PMID:11985581</ref> 
== 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/vz/2vzk_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=2vzk ConSurf].
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== Publication Abstract from PubMed ==
Acyl-enzyme complexes are intermediates in reactions catalyzed by many hydrolases and related enzymes which employ nucleophilic catalysis. However, most of the reported structural data on acyl-enzyme complexes has been acquired under noncatalytic conditions. Recent IR analyses have indicated that some acyl-enzyme complexes may be more flexible than most crystallographic analyses have implied. OAT2 is a member of the N-terminal nucleophile (Ntn) hydrolase enzyme superfamily and catalyzes the reversible transfer of an acetyl group between the alpha-amino groups of ornithine and glutamate in a mechanism proposed to involve an acyl-enzyme complex. We have carried out biophysical analyses on ornithine acetyl transferase (OAT2), both in solution and in the crystalline state. Mass spectrometric studies identified Thr-181 as the residue acetylated during OAT2 catalysis; (13)C NMR analyses implied the presence of an acyl-enzyme complex in solution. Crystallization of OAT2 in the presence of N-alpha-acetyl-l-glutamate led to a structure in which Thr-181 was acetylated; the carbonyl oxygen of the acyl-enzyme complex was located in an oxyanion hole and positioned to hydrogen bond with the backbone amide NH of Gly-112 and the alcohol of Thr-111. While the crystallographic analyses revealed only one structure, IR spectroscopy demonstrated the presence of two distinct acyl-enzyme complex structures with carbonyl stretching frequencies at 1691 and 1701 cm(-1). Modeling studies implied two possible acyl-enzyme complex structures, one of which correlates with that observed in the crystal structure and with the 1691 cm(-1) IR absorption. The second acyl-enzyme complex structure, which has only a single oxyanion hole hydrogen bond, is proposed to give rise to the 1701 cm(-1) IR absorption. The two acyl-enzyme complex structures can interconvert by movement of the Thr-111 side-chain alcohol hydrogen away from the oxyanion hole to hydrogen bond with the backbone carbonyl of the acylated residue, Thr-181. Overall, the results reveal that acyl-enzyme complex structures may be more dynamic than previously thought and support the use of a comprehensive biophysical and modeling approach in studying such intermediates.

Anatomy of a Simple Acyl Intermediate in Enzyme Catalysis: Combined Biophysical and Modeling Studies on Ornithine Acetyl Transferase.,Iqbal A, Clifton IJ, Bagonis M, Kershaw NJ, Domene C, Claridge TD, Wharton CW, Schofield CJ J Am Chem Soc. 2008 Dec 23. PMID:19105697<ref>PMID:19105697</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 2vzk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Streptomyces clavuligerus]]
[[Category: Clifton IJ]]
[[Category: Iqbal A]]
[[Category: Schofield CJ]]