View source for 5x9m


==Structure of hyper-sweet thaumatin (D21N)==
<StructureSection load='5x9m' size='340' side='right'caption='[[5x9m]], [[Resolution|resolution]] 0.93&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5x9m]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Thaumatococcus_daniellii Thaumatococcus daniellii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5X9M OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5X9M 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]] 0.93&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=TLA:L(+)-TARTARIC+ACID'>TLA</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=5x9m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5x9m OCA], [https://pdbe.org/5x9m PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5x9m RCSB], [https://www.ebi.ac.uk/pdbsum/5x9m PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5x9m ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/THM1_THADA THM1_THADA] Taste-modifying protein; intensely sweet-tasting. It is 100000 times sweeter than sucrose on a molar basis.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
One of the sweetest proteins found in tropical fruits (with a threshold of 50nM), thaumatin, is also used commercially as a sweetener. Our previous study successfully produced the sweetest thaumatin mutant (D21N), designated hyper-sweet thaumatin, which decreases the sweetness threshold to 31nM. To investigate why the D21N mutant is sweeter than wild-type thaumatin, we compared the structure of the D21N mutant solved at a subatomic resolution of 0.93A with that of wild-type thaumatin determined at 0.90A. Although the overall structure of the D21N mutant resembles that of wild-type thaumatin, our subatomic resolution analysis successfully assigned and discriminated the detailed atomic positions of side-chains at position 21. The relative B-factor value of the side-chain at position 21 in the D21N mutant was higher than that of wild-type thaumatin, hinting at a greater flexibility of side-chain at 21 in the hyper-sweet D21N mutant. Furthermore, alternative conformations of Lys19, which is hydrogen-bonded to Asp21 in wild-type, were found only in the D21N mutant. Subatomic resolution analysis revealed that flexible conformations at the sites adjacent to positions 19 and 21 play a crucial role in enhancing sweet potency and may serve to enhance the complementarity of electrostatic potentials for interaction with the sweet taste receptor.

Subatomic structure of hyper-sweet thaumatin D21N mutant reveals the importance of flexible conformations for enhanced sweetness.,Masuda T, Okubo K, Murata K, Mikami B, Sugahara M, Suzuki M, Temussi PA, Tani F Biochimie. 2019 Feb;157:57-63. doi: 10.1016/j.biochi.2018.10.020. Epub 2018 Oct, 31. PMID:30389513<ref>PMID:30389513</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5x9m" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thaumatococcus daniellii]]
[[Category: Masuda T]]
[[Category: Mikami B]]
[[Category: Okubo K]]
[[Category: Sugahara M]]
[[Category: Suzuki M]]