Calorimetric evaluation of the irreversible nucleation process from the reversible oligomers of denatured proteins and its application

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05288
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 37020:Chemistry and chemical methodology of biomolecules-related
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Kidokoro Shun-ichi 長岡技術科学大学, 工学研究科, 教授 (80195320)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 示差走査熱量測定 / 反応エンタルピー / アミロイド線維 / 会合核依存的伸長モデル / 速度定数

Outline of Final Research Achievements

Regarding the mechanism of amyloid fibril formation, which is related to many diseases, we focused on the irreversible process of the assembly nucleation of amyloid fibrils from the reversible assembly of several molecules (RO state) formed by the denatured state of protein molecules, and developed a method of global analysis of DSC data at multiple protein concentrations and temperature scanning rates with a set of equilibrium and kinetic parameters, and applied it to actual data, using a protein in which the RO state appears as a reversible intermediate state of the thermal transition. We also created several amino acid mutants where the stability of RO is designed, and it was shown that increased RO stability leads to enhanced amyloid fibril formation. The new methods have been developed and important knowledge have been accumulated about the relationship between the RO state and amyloid fibril formation.

Free Research Field

蛋白質物性学

Academic Significance and Societal Importance of the Research Achievements

蛋白質の変性状態の可逆的な会合体(RO)形成については、多くの蛋白質で平衡論的によって確認されているが、未だ一般的な現象として認知されてはいない。本研究では、ROの安定性制御への分子表面の疎水性残基の役割を更に明確化するとともに、それらがアミロイド線維形成反応にも関与することを明確にしており、蛋白質物性の基礎的な知見としても、また疾病予防や治療につながるアミロイド線維形成を制御するための応用研究につながる知見としても重要と考えられる。また、温度走査熱量測定によって、平衡論的な転移と同時に速度論的な反応を観測する試みは挑戦的であり、様々な他の現象への応用が可能で波及効果が高いと考えられる。