View source for 1ai3


==ORBITAL STEERING IN THE CATALYTIC POWER OF ENZYMES: SMALL STRUCTURAL CHANGES WITH LARGE CATALYTIC CONSEQUENCES==
<StructureSection load='1ai3' size='340' side='right'caption='[[1ai3]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ai3]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AI3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AI3 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]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ICT:ISOCITRIC+ACID'>ICT</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NDO:NICOTINAMIDE-(6-DEAMINO-6-HYDROXY-ADENINE)-DINUCLEOTIDE+PHOSPHATE'>NDO</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=1ai3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ai3 OCA], [https://pdbe.org/1ai3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ai3 RCSB], [https://www.ebi.ac.uk/pdbsum/1ai3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ai3 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/IDH_ECOLI IDH_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/ai/1ai3_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1ai3 ConSurf].
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== Publication Abstract from PubMed ==
Small structural perturbations in the enzyme isocitrate dehydrogenase (IDH) were made in order to evaluate the contribution of precise substrate alignment to the catalytic power of an enzyme. The reaction trajectory of IDH was modified (i) after the adenine moiety of nicotinamide adenine dinucleotide phosphate was changed to hypoxanthine (the 6-amino was changed to 6-hydroxyl), and (ii) by replacing Mg2+, which has six coordinating ligands, with Ca2+, which has eight coordinating ligands. Both changes make large (10(-3) to 10(-5)) changes in the reaction velocity but only small changes in the orientation of the substrates (both distance and angle) as revealed by cryocrystallographic trapping of active IDH complexes. The results provide evidence that orbital overlap produced by optimal orientation of reacting orbitals plays a major quantitative role in the catalytic power of enzymes.

Orbital steering in the catalytic power of enzymes: small structural changes with large catalytic consequences.,Mesecar AD, Stoddard BL, Koshland DE Jr Science. 1997 Jul 11;277(5323):202-6. PMID:9211842<ref>PMID:9211842</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 1ai3" style="background-color:#fffaf0;"></div>

==See Also==
*[[Isocitrate dehydrogenase 3D structures|Isocitrate dehydrogenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Koshland Junior DE]]
[[Category: Mesecar A]]
[[Category: Stoddard BL]]