Five amino acid residues in cysteine-rich domain of human T1R3 were involved in the response for sweet-tasting protein, thaumatin

被引：25

作者：

Masuda, Tetsuya ^{[1
]}

Taguchi, Wakana ^{[1
]}

Sano, Ayane ^{[1
]}

Ohta, Keisuke ^{[1
]}

Kitabatake, Naofumi ^{[2
]}

Tani, Fumito ^{[1
]}

机构：

[1] Kyoto Univ, Grad Sch Agr, Div Food Sci & Biotechnol, Uji, Kyoto 6110011, Japan

[2] Notre Dame Seishin Univ, Dept Foods & Human Nutr, Okayama 7008516, Japan

来源：

BIOCHIMIE | 2013年 / 95卷 / 07期

基金：

日本学术振兴会;

关键词：

Thaumatin; Sweet-tasting protein; Sweet receptor; Cysteine-rich domain; MAMMALIAN SWEET; RECEPTORS; BRAZZEIN; REGIONS;

D O I：

10.1016/j.biochi.2013.01.010

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Thaumatin, a sweet-tasting plant protein, elicits a sweet taste sensation at 50 nM in humans but not rodents. Although it was shown that the cysteine-rich domain (CRD) of human T1R3 (hT1R3) is important for the response to thaumatin, the amino acid residues within CRD critical for response are still unknown. A comparison of the amino acid sequence (69 amino acid residues) of CRD between hT1R3 and mouse T1R3 (mT1R3) revealed sixteen amino acids that differ. In the present study, we converted each of these sixteen amino acids in hT1R3 to their mouse counterpart and examined the response to thaumatin and sucralose using a cell-based assay. No significant decrease in the response to sucralose was seen among any of the sixteen mutants. However, five mutants (Q504K, A537T, R556P, S559P, and R560K) exhibited a significantly diminished response to thaumatin. The five critical residues involved in the response to thaumatin were dispersed in the CRD of hT1R3 and widely distributed when compared to brazzein. The unique intense sweet-taste of thaumatin might be attributed to the different receptor activation mechanism compared to the small molecule sweetener sucralose. (C) 2013 Elsevier Masson SAS. All rights reserved.

引用

页码：1502 / 1505

页数：4

共 22 条

[1] Key Amino Acid Residues Involved in Multi-Point Binding Interactions between Brazzein, a Sweet Protein, and the T1R2-T1R3 Human Sweet Receptor [J].