1csi: Difference between revisions

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New page: left|200px<br /><applet load="1csi" size="450" color="white" frame="true" align="right" spinBox="true" caption="1csi, resolution 1.70Å" /> '''A VERY SHORT HYDROGE...
 
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[[Image:1csi.gif|left|200px]]<br /><applet load="1csi" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1csi, resolution 1.70&Aring;" />
'''A VERY SHORT HYDROGEN BOND PROVIDES ONLY MODERATE STABILIZATION OF AN ENZYME: INHIBITOR COMPLEX OF CITRATE SYNTHASE'''<br />


==Overview==
==A very short hydrogen bond provides only moderate stabilization of an enzyme: inhibitor complex of citrate synthase==
Two extremely potent inhibitors of citrate synthase, carboxyl and primary, amide analogues of acetyl coenzyme A, have been synthesized. The ternary, complexes of these inhibitors with oxaloacetate and citrate synthase have, been crystallized and their structures analyzed at 1.70- and 1.65-A, resolution, respectively. The inhibitors have dissociation constants in, the nanomolar range, with the carboxyl analogue binding more tightly (Ki =, 1.6 nM at pH 6.0) than the amide analogue (28 nM), despite the unfavorable, requirement for proton uptake by the former. The carboxyl group forms a, shorter hydrogen bond with the catalytic Asp 375 (distance &lt; 2.4 A) than, does the amide group (distance approximately 2.5 A). Particularly with the, carboxylate inhibitor, the very short hydrogen bond distances measured, suggest a low barrier or short strong hydrogen bond. However, the binding, constants differ by only a factor of 20 at pH 6.0, corresponding to an, increase in binding energy for the carboxyl analogue on the enzyme of, about 2 kcal/mol more than the amide analogue, much less than has been, proposed for short strong hydrogen bonds based on gas phase measurements, [&gt; 20 kcal/mol (Gerlt &amp; Gassman, 1993a,b)]. The inhibitor complexes, support proposals that Asp 375 and His 274 work in concert to form an, enolized form of acetyl-coenzyme A as the first step in the reaction.
<StructureSection load='1csi' size='340' side='right'caption='[[1csi]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1csi]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CSI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CSI 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]] 1.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CMX:CARBOXYMETHYLDETHIA+COENZYME+*A'>CMX</scene>, <scene name='pdbligand=OAA:OXALOACETATE+ION'>OAA</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=1csi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1csi OCA], [https://pdbe.org/1csi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1csi RCSB], [https://www.ebi.ac.uk/pdbsum/1csi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1csi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CISY_CHICK CISY_CHICK]
== 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/cs/1csi_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=1csi ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1CSI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with OAA and CMX as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Citrate_(Si)-synthase Citrate (Si)-synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.3.1 2.3.3.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1CSI OCA].
*[[Citrate Synthase 3D structures|Citrate Synthase 3D structures]]
 
__TOC__
==Reference==
</StructureSection>
A very short hydrogen bond provides only moderate stabilization of an enzyme-inhibitor complex of citrate synthase., Usher KC, Remington SJ, Martin DP, Drueckhammer DG, Biochemistry. 1994 Jun 28;33(25):7753-9. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8011640 8011640]
[[Category: Citrate (Si)-synthase]]
[[Category: Gallus gallus]]
[[Category: Gallus gallus]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Remington, S.J.]]
[[Category: Remington SJ]]
[[Category: Usher, K.C.]]
[[Category: Usher KC]]
[[Category: CMX]]
[[Category: OAA]]
[[Category: lyase(oxo-acid)]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 12:43:27 2007''

Latest revision as of 09:45, 7 February 2024

A very short hydrogen bond provides only moderate stabilization of an enzyme: inhibitor complex of citrate synthaseA very short hydrogen bond provides only moderate stabilization of an enzyme: inhibitor complex of citrate synthase

Structural highlights

1csi is a 1 chain structure with sequence from Gallus gallus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.7Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CISY_CHICK

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1csi, resolution 1.70Å

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