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Title: A Hypersweet Protein: Removal of The Specific Negative Charge at Asp21 Enhances Thaumatin Sweetness.
Authors: Masuda, Tetsuya  kyouindb  KAKEN_id  orcid https://orcid.org/0000-0001-5857-5753 (unconfirmed)
Ohta, Keisuke
Ojiro, Naoko
Murata, Kazuki
Mikami, Bunzo  kyouindb  KAKEN_id
Tani, Fumito  kyouindb  KAKEN_id
Temussi, Piero Andrea
Kitabatake, Naofumi
Author's alias: 桝田, 哲哉
Issue Date: 3-Feb-2016
Publisher: Nature Publishing Group
Journal title: Scientific reports
Volume: 6
Thesis number: 20255
Abstract: Thaumatin is an intensely sweet-tasting protein that elicits sweet taste at a concentration of 50 nM, a value 100,000 times larger than that of sucrose on a molar basis. Here we attempted to produce a protein with enhanced sweetness by removing negative charges on the interacting side of thaumatin with the taste receptor. We obtained a D21N mutant which, with a threshold value 31 nM is much sweeter than wild type thaumatin and, together with the Y65R mutant of single chain monellin, one of the two sweetest proteins known so far. The complex model between the T1R2-T1R3 sweet receptor and thaumatin, derived from tethered docking in the framework of the wedge model, confirmed that each of the positively charged residues critical for sweetness is close to a receptor residue of opposite charge to yield optimal electrostatic interaction. Furthermore, the distance between D21 and its possible counterpart D433 (located on the T1R2 protomer of the receptor) is safely large to avoid electrostatic repulsion but, at the same time, amenable to a closer approach if D21 is mutated into the corresponding asparagine. These findings clearly confirm the importance of electrostatic potentials in the interaction of thaumatin with the sweet receptor.
Description: 甘味タンパク質の高甘味度化に成功 -低カロリータンパク質性甘味料の更なる有効利用に期待-. 京都大学プレスリリース. 2016-02-04.
Rights: This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
URI: http://hdl.handle.net/2433/204388
DOI(Published Version): 10.1038/srep20255
PubMed ID: 26837600
Related Link: http://www.kyoto-u.ac.jp/ja/research/research_results/2015/160203_1.html
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