Studies on the structure-function relationships in sweet-tasting proteins and the effects of the masking of bitterness by sweet-tasting proteins

2015 Fiscal Year Final Research Report

• Project/Area Number: 25450167
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Food science
• Research Institution: Kyoto University
• Principal Investigator: masuda tetsuya 京都大学, (連合)農学研究科(研究院), 助教 (80311744)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 甘味タンパク質 / ソーマチン / Ｘ線結晶構造解析 / 室温構造解析 / 苦味抑制

Outline of Final Research Achievements

The structure of recombinant thaumatin II was determined at the resolution of 0.99Å. The flexible conformations in two critical residues were important for interaction with sweet taste receptors. We introduced a grease-matrix carrier for protein microcrystals and obtained the structure of thaumatin under ambient conditions by Serial femtosecond X-ray crystallography.
We successfully obtained a protein with enhanced sweetness by removing negative charges on the interacting side of thaumatin. The complex model between sweet receptor and thaumatin 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. We prepared the HEK cells stably expressing bitter receptors and ascertained the effect of the masking of bitterness by thaumatin.

Free Research Field

食品生化学