5x9l

Recombinant thaumatin I at 0.9 Angstrom

spinqualitylabelsall models 5x9l, resolution 0.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5x9l is a 1 chain structure with sequence from Thaumatococcus daniellii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 0.9Å Ligands: GOL, TLA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function THM1_THADA Taste-modifying protein; intensely sweet-tasting. It is 100000 times sweeter than sucrose on a molar basis. 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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