2018 Fiscal Year Final Research Report
Structural study of a huge respiratory supermolecule hemocyanin (international collaboration work)(Fostering Joint International Research)
| Project/Area Number |
15KK0248
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| Research Category |
Fund for the Promotion of Joint International Research (Fostering Joint International Research)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Structural biochemistry
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| Research Institution | Tohoku University (2017-2018)
Hokkaido University (2015-2016) |
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Principal Investigator |
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| Research Collaborator |
Raunser Stefan Max Planck Institute of Molecular Physiology, ディレクター
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| Project Period (FY) |
2015 – 2018
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| Keywords | ヘモシアニン / 立体構造 / クライオ電顕 / 対称性 |
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| Outline of Final Research Achievements |
Hemocyanin is an oxygen transporter of mollusks. Squid hemocyanin is a huge cylindrical protein complex with a molecular mass approximately 4 MDa. In a previous study, we determined crystal structure of squid hemocyanin at 3.0 angstrom resolution. However, due to the crystal packing and symmetry of the outer wall region, we could not determine precise structure of the inside domains. Therefore, in the present study, we used cryo-electrom microscopy single particle analysis method to determine the structure. The revealed strcutre showed that the inner domains are arranged asymmetrically. As well, insight into molecular evolution of hemocyanin was revealed.
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| Free Research Field |
構造生物学
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| Academic Significance and Societal Importance of the Research Achievements |
X線結晶構造解析では結晶中の全ての分子の平均構造が得られるため，外壁領域と内部領域の対称性が異なる場合，分子同士の接触に影響を与える外壁領域の影響を受けやすい．先行研究にてイカヘモシアニンのX線結晶構造解析を行った際も，D5対称性を持つ外壁領域の影響を受け，内部の構造もD5の対称性で平均化され，その正確な構造を決定できなかった．本研究では，外部領域と内部領域を個別に精密化することができるクライオ電子顕微鏡単粒子解析法を用いることにより，ヘモシアニンの非対称な内部構造を決定することができた．本研究により，対称性がミスマッチした分子の構造解析におけるクライオ電子顕微鏡解析の有用性が示された．
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