2022 Fiscal Year Final Research Report
Functional enhancement and application to food materials of plant proteins based on structural analysis
| Project/Area Number |
20K05875
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 38050:Food sciences-related
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| Research Institution | Ryukoku University (2021-2022)
Kyoto University (2020) |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | taste / sweet / atomic resolution / X-ray crystallography |
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| Outline of Final Research Achievements |
The sweetness of thaumatin remains when heating under acidic conditions, but it disappears when heating at a pH above 7. To assess this phenomenon more in detail, X-ray crystal structures analysis and the melting temperature (Tm) of thaumatin were examined. The Tm of thaumatin at pH 4 was substantially reduced when compared to pH 6, suggesting thermal unfolding of thaumatin at pH 4 was occurred in lower temperature than at pH 6. The structural comparisons among different pH values revealed overall B-factor value of structure at pH 4 was indeed higher than those at pH 6 and 8, but the relative B-factor values for most lysine residues tended to decrease on lowering the pH. These results suggested that structure at pH 4 becomes more flexible and feasible to be unfolding than at pH 6.and 8, but reduction of relative flexibility of the specific lysine residues might play important roles to prevent thermal aggregation under acidic conditions, thereby maintain sweetness.
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| Free Research Field |
食品科学、構造生物化学
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| Academic Significance and Societal Importance of the Research Achievements |
原子レベルでの構造解析により、ソーマチンの熱安定性や、熱凝集に寄与する構造要因を明らかにすることで、その他多くの食品タンパク質に対しても、構造安定性の強化や熱凝集性を抑制できる手法を構築し、新規植物由来の食品素材の開発に繋げたい。
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