High-speed AFM observation of archaeal MCM protein complexes

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K15433
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical pharmacy
• Research Institution: Microbial Chemistry Research Foundation (2018); Kanazawa University (2017)
• Principal Investigator: NOSHIRO Daisuke 公益財団法人微生物化学研究会, 微生物化学研究所, 博士研究員 (90751107)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 高速原子間力顕微鏡 / ヘリカーゼ / ATPase / 観察基板 / タマビジン2 / 二次元結晶

Outline of Final Research Achievements

Two archaeal MCM (ssoMCM and mthMCM) proteins which have helicase activities to unwind double-stranded DNA to produce single-stranded DNA were observed by high-speed AFM (HS-AFM). The observation of the full-length ssoMCM protein on mica surface revealed the formation of ladder-like long-shaped oligomers and ring (or partial ring) structures composed of more than hexamer as well as hexameric ring structure with helicase activity (or partial hexameric ring structure). In addition, observation of biotinylated full-length mthMCM protein on the 2D crystals of tamavidin 2 confirmed the formation of hexameric ring and double hexameric ring (12 mer) structures.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

高速AFMを用いて、フレキシブルなC末端を含めた全長の古細菌由来MCMタンパク質を観察した結果、MCMタンパク質が六量体リング以外の多量体構造を形成し得ることを明らかにした。また、本研究の遂行過程で発見されたタマビジン２の二次元結晶をマイカ上に直接形成させる方法は、ビオチンを導入した生体分子の固定基板の簡便で迅速な作製法として有用であり、他の研究にも利用することができる。