View source for 6had


==Human transketolase variant E160Q==
<StructureSection load='6had' size='340' side='right'caption='[[6had]], [[Resolution|resolution]] 1.04&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6had]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HAD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6HAD FirstGlance]. <br>
</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=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=TPP:THIAMINE+DIPHOSPHATE'>TPP</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[6ha3|6ha3]]</div></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Transketolase Transketolase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.2.1.1 2.2.1.1] </span></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=6had FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6had OCA], [https://pdbe.org/6had PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6had RCSB], [https://www.ebi.ac.uk/pdbsum/6had PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6had ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/TKT_HUMAN TKT_HUMAN]] 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 ==
The underlying molecular mechanisms of cooperativity and allosteric regulation are well understood for many proteins, with haemoglobin and aspartate transcarbamoylase serving as prototypical examples(1,2). The binding of effectors typically causes a structural transition of the protein that is propagated through signalling pathways to remote sites and involves marked changes on the tertiary and sometimes even the quaternary level(1-5). However, the origin of these signals and the molecular mechanism of long-range signalling at an atomic level remain unclear(5-8). The different spatial scales and timescales in signalling pathways render experimental observation challenging; in particular, the positions and movement of mobile protons cannot be visualized by current methods of structural analysis. Here we report the experimental observation of fluctuating low-barrier hydrogen bonds as switching elements in cooperativity pathways of multimeric enzymes. We have observed these low-barrier hydrogen bonds in ultra-high-resolution X-ray crystallographic structures of two multimeric enzymes, and have validated their assignment using computational calculations. Catalytic events at the active sites switch between low-barrier hydrogen bonds and ordinary hydrogen bonds in a circuit that consists of acidic side chains and water molecules, transmitting a signal through the collective repositioning of protons by behaving as an atomistic Newton's cradle. The resulting communication synchronizes catalysis in the oligomer. Our studies provide several lines of evidence and a working model for not only the existence of low-barrier hydrogen bonds in proteins, but also a connection to enzyme cooperativity. This finding suggests new principles of drug and enzyme design, in which sequences of residues can be purposefully included to enable long-range communication and thus the regulation of engineered biomolecules.

Low-barrier hydrogen bonds in enzyme cooperativity.,Dai S, Funk LM, von Pappenheim FR, Sautner V, Paulikat M, Schroder B, Uranga J, Mata RA, Tittmann K Nature. 2019 Sep;573(7775):609-613. doi: 10.1038/s41586-019-1581-9. Epub 2019 Sep, 18. PMID:31534226<ref>PMID:31534226</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 6had" style="background-color:#fffaf0;"></div>

==See Also==
*[[Transketolase|Transketolase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Transketolase]]
[[Category: Dai, S]]
[[Category: Sautner, V]]
[[Category: Tittmann, K]]
[[Category: Catalysis]]
[[Category: Enzyme]]
[[Category: Sugar metabolism]]
[[Category: Thdp]]
[[Category: Thiamin diphosphate]]
[[Category: Tpp]]
[[Category: Transferase]]