Development of a selective BRD4 inhibitor by neutron protein crystallographic analysis

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K07012
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 47020:Pharmaceutical analytical chemistry and physicochemistry-related
• Research Institution: University of Toyama
• Principal Investigator: Yokoyama Takeshi 富山大学, 学術研究部薬学・和漢系, 助教 (50524162)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 中性子結晶構造解析 / BRD4 / 等温滴定カロリメトリー / イソリキリチゲニン / エンタルピー / 水素結合 / 水分子クラスター / ブロモドメイン

Outline of Final Research Achievements

Neutron crystal structure of the BRD4-inhibitor complex was successfully determined, and the positions and occupancies of the hydrogen and deuterium atoms in the protein were precisely determined. This analysis revealed the whole picture of the hydrogen bond network of the water cluster located at the substrate binding site. In addition, the binding of isoliquiritigenin to BRD4 was shown to be enthalpy-driven by isothermal titration calorimetry, suggesting that isoliquiritigenin have an advantage in selective binding to BRD4. Previous X-ray crystallography showed that the binding of isoliquiritigenin to BRD4 induced an arrangement of the water clusters. Collectively, the favorable enthalpy change in the binding of isoliquiritigenin to BRD4 could be obtained by the rearrangement of the hydrogen bond network of the water cluster.

Free Research Field

構造生物学

Academic Significance and Societal Importance of the Research Achievements

BRD4を阻害する化合物はさまざまながんに対する治療薬になると期待されている。しかし、ブロモドメインをもつタンパク質は多くあるため、副作用の観点から特異的にBRD4に結合し、その機能を阻害する薬剤の開発が望まれている。本研究の成果は、選択的結合に適した官能基と結合様式を同定したことであり、選択的BRD4阻害剤の開発を進めるうえで重要な知見を得ることができた。