2021 Fiscal Year Final Research Report
Flexibility and plasticity of the tubulin lattice within assembled microtubules
| Project/Area Number |
19K06602
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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 43040:Biophysics-related
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| Research Institution | Chuo University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 微小管 / X線繊維回折法 / 小角散乱 / 微小管安定化剤 / 流動配向法 / 負の熱膨張係数 / チューブリン |
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| Outline of Final Research Achievements |
We investigated the dynamic changes of X-ray fiber diffraction from brain microtubules (MTs) on rapid cooling at SPring-8. This is the first example to show the temperature-dependent structural dynamics of supramolecular compounds, and we obtained the following four new findings. The first is that MTs have the different rate of shrinkage on cooling in the length and diameter directions, which is a direct proof that tubulin molecules undergo structural changes at low temperature. The second is that 17 degrees is the critical temperature at which the MT structure can be maintained, the third is that the cooling shrinkage rate clearly changed depending on MT stabilizers (paclitaxel and laulimalide), and the fourth is that the difference in structures between depolymerization and repolymerization was observed by investigating diffraction patterns during re-warming. This study would be an epoch-making one that is proposing a new tool to investigate the dynamic features of MT structures.
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| Free Research Field |
生物物理学
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| Academic Significance and Societal Importance of the Research Achievements |
生体分子は独特の高次構造を持ち、金属粒子やポリマー粒子とは異なり、非等方的な構造を持つ。温度変化による熱膨張率もその構造を反映していると期待できる。本研究は、この点を高精度のサブpmスケールで明らかにした最初の研究例となる。研究手法上、冷却しなければならないクライオEMで解明された分子構造を解釈する上で、程度の差はあれ、低温構造変化する生体分子もある点は、考慮すべき新事実である。また、低温条件下で哺乳類の脳微小管は不安定化する性質があるが、その生物物理学的な説明、さらには、より温度順応型の他の真核生物から、哺乳類の微小管が進化して来た理由や分子進化プロセスの理解にもつながると期待している。
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