ミオシンVIにおける大きなハンド・オーバー・ハンドと小さなインチワームのようなステップを切り替える
So Nishikawa1, Ikuo Arimoto, Keigo Ikezaki
1Graduate School of Frontier Biosciences, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan.
Cell
|September 21, 2010
まとめ
ミオシンVIモーターは,驚くほど大きく,ステップサイズが変化します. この研究は,2つの異なるステップメカニズムを明らかにし,ハンド・オーバー・ハンドとインチワームのようなメカニズムで,汎用的な細胞機能を可能にします.
科学分野:
- 分子生物学は分子生物学である.
- 細胞生物物理学 細胞生物物理学
背景:
- 生物学的モータータンパク質は,通常,その構造に基づいて予測可能なステップサイズを示します.
- Myosin VIは,短いレバーアームによって予測されるよりも,より大きく,より多様なステップサイズを表示する顕著な例外を示しています.
研究 の 目的:
- ミオシンVIの予測されたステップサイズと観測されたステップサイズとの差異を解決する.
- ミオシンVIの大規模で変化するステップサイズに起因する根本的なメカニズムを解明する.
主な方法:
- 高感度ナノ画像を用いて,ミオシンVIモータードメインに結合した量子ドット (Qdots) と金ナノ粒子をモニタリングした.
- 分析は,ステップサイズと運動活動中の分布を定量化することに焦点を当てました.
主要な成果:
- ミオシンVIは2つの異なるステップサイズを示します:72nmの大きなステップと44nmの小さなステップです.
- 大きなステップサイズは,拡張され,硬直なレバーアームに起因し,変動性は2つの異なる傾斜角度 (パワーストロックの前および後の状態) から生じる.
- 小さなステップの頻度はADPと共に増加し,ADPに依存するメカニズムを示唆しています.
結論:
- ミオシンVIは2つのステップメカニズムを使用しています:大きなステップでは手と手のメカニズム,小さなステップではインチワームのようなメカニズムです.
- モーターは動的にこれらのメカニズムの間で,ストレスの敏感でADPに依存した方法でスイッチします.
- この適応性により,ミオシンVIは,膀の輸送と膜の固定を含む多様な細胞の役割を担うことができます.
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