View source for 5xsa


==Crystal Structure of Transketolase in complex with TPP intermediate III from Pichia Stipitis==
<StructureSection load='5xsa' size='340' side='right'caption='[[5xsa]], [[Resolution|resolution]] 0.97&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5xsa]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Scheffersomyces_stipitis_CBS_6054 Scheffersomyces stipitis CBS 6054]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5XSA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5XSA 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]] 0.975&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=8EL:2-[3-[(4-azanyl-2-methyl-pyrimidin-5-yl)methyl]-4-methyl-2H-1,3-thiazol-5-yl]ethyl+phosphono+hydrogen+phosphate'>8EL</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</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=5xsa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5xsa OCA], [https://pdbe.org/5xsa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5xsa RCSB], [https://www.ebi.ac.uk/pdbsum/5xsa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5xsa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TKT_PICST TKT_PICST] Catalyzes the transfer of a two-carbon ketol group from a ketose donor to an aldose acceptor, via a covalent intermediate with the cofactor thiamine pyrophosphate.
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== Publication Abstract from PubMed ==
It is theoretically plausible that thiazolium mesomerizes to congeners other than carbene in a low effective dielectric binding site; especially given the energetics and uneven electronegativity of carbene groups. However, such a phenomenon has never been reported. Nine crystal structures of transketolase obtained from Pichia stipitis (TKps) are reported with subatomic resolution, where thiazolium displays an extraordinary ring-bending effect. The bent thiazolium congeners correlate with non-Kekule diradicals because there is no gain or loss of electrons. In conjunction with biophysical and biochemical analyses, it is concluded that ring bending is a result of tautomerization of thiazolium with its non- Kekule diradicals, exclusively in the binding site of TKps. The chemophysical properties of these thiazolium mesomers may account for the great variety of reactivities carried out by thiamine-diphosphate-containing (ThDP) enzymes. The stability of ThDP in living systems can be regulated by the levels of substrates, and hydration and dehydration, as well as diradical-mediated oxidative degradation.

The Mesomeric Effect of Thiazolium on non-Kekule Diradicals in Pichia stipitis Transketolase.,Hsu NS, Wang YL, Lin KH, Chang CF, Lyu SY, Hsu LJ, Liu YC, Chang CY, Wu CJ, Li TL Angew Chem Int Ed Engl. 2018 Feb 12;57(7):1802-1807. doi: 10.1002/anie.201709799., Epub 2018 Jan 15. PMID:29243887<ref>PMID:29243887</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 5xsa" style="background-color:#fffaf0;"></div>

==See Also==
*[[Transketolase 3D structures|Transketolase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Scheffersomyces stipitis CBS 6054]]
[[Category: Hsu NS]]
[[Category: Li TL]]
[[Category: Wang YL]]