View source for 7wrr


==X-ray structure of Thermus thermophilus HB8 transketorase in complex with TPP and MES==
<StructureSection load='7wrr' size='340' side='right'caption='[[7wrr]], [[Resolution|resolution]] 2.01&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7wrr]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB8 Thermus thermophilus HB8]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7WRR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7WRR 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]] 2.01&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene>, <scene name='pdbligand=TPP:THIAMINE+DIPHOSPHATE'>TPP</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=7wrr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7wrr OCA], [https://pdbe.org/7wrr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7wrr RCSB], [https://www.ebi.ac.uk/pdbsum/7wrr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7wrr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q5SM35_THET8 Q5SM35_THET8] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Transketolase is a key enzyme in the pentose phosphate pathway in all organisms, recognizing sugar phosphates as substrates. Transketolase with a cofactor of thiamine pyrophosphate catalyzes the transfer of a 2-carbon unit from D-xylulose-5-phosphate to D-ribose-5-phosphate (5-carbon aldose), giving D-sedoheptulose-7-phosphate (7-carbon ketose). Transketolases can also recognize non-phosphorylated monosaccharides as substrates, and catalyze the formation of non-phosphorylated 7-carbon ketose (heptulose), which has attracted pharmaceutical attention as an inhibitor of sugar metabolism. Here, we report the structural and biochemical characterizations of transketolase from Thermus thermophilus HB8 (TtTK), a well-characterized thermophilic Gram-negative bacterium. TtTK showed marked thermostability with maximum enzyme activity at 85 degrees C, and efficiently catalyzed the formation of heptuloses from lithium hydroxypyruvate and four aldopentoses: D-ribose, L-lyxose, L-arabinose, and D-xylose. The X-ray structure showed that TtTK tightly forms a homodimer with more interactions between subunits compared with transketolase from other organisms, contributing to its thermal stability. A modeling study based on X-ray structures suggested that D-ribose and L-lyxose could bind to the catalytic site of TtTK to form favorable hydrogen bonds with the enzyme, explaining the high conversion rates of 41% (D-ribose) and 43% (L-lyxose) to heptulose. These results demonstrate the potential of TtTK as an enzyme producing a rare sugar of heptulose. KEY POINTS: * Transketolase catalyzes the formation of a 7-carbon sugar phosphate * Structural and biochemical characterizations of thermophilic transketolase were done * The enzyme could produce non-phosphorylated 7-carbon ketoses from sugars.

Structural and biochemical characterizations of Thermus thermophilus HB8 transketolase producing a heptulose.,Yoshihara A, Takamatsu Y, Mochizuki S, Yoshida H, Masui R, Izumori K, Kamitori S Appl Microbiol Biotechnol. 2022 Nov 28. doi: 10.1007/s00253-022-12297-z. PMID:36441206<ref>PMID:36441206</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7wrr" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus thermophilus HB8]]
[[Category: Kamitori S]]
[[Category: Yoshihara A]]