球状タンパク質内の異なる種類のアミノ酸残基の温度依存のダイナミックトランジション
Yinglong Miao1, Zheng Yi, Dennis C Glass
1University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Journal of the American Chemical Society
|November 13, 2012
まとめ
タンパク質のダイナミクスを研究することで,温度がアミノ酸残基の移動にどのように影響するかが明らかになる. 排水性残基が最初に活性化し,温度上昇に伴い,排水性残基が次に活性化します.
科学分野:
- バイオフィジックス 生物物理学
- コンピュータ生物学 コンピュータ生物学
- タンパク質のダイナミクス
背景:
- サイトクロームP450camは,薬物代謝と解毒に関与する重要な酵素です.
- タンパク質の動態を理解することは,酵素の機能とメカニズムを明らかにするために不可欠です.
- アミノ酸残留のダイナミクスは,タンパク質の柔軟性と活性において重要な役割を果たします.
研究 の 目的:
- サイトクロームP450cam.cam.の異なるアミノ酸残留クラスにおける温度に依存するナノ秒ダイナミクスを調査する.
- 温度によって引き起こされる形状の変化における,水害性,芳香性,および水性性残留物の相互作用を解明する.
- 残留ダイナミクスを水素結合と水素水相互作用と相関させるため.
主な方法:
- 弾性非一貫性ニュートロン散乱 (EINS) 実験は,原子の運動を調査するために実施されました.
- 分子動力学 (MD) シミュレーションは,原子レベルでタンパク質の行動をモデル化するために使用されました.
- EINSとMDのアプローチを組み合わせることで,タンパク質のダイナミクスに関する補完的な洞察が得られました.
主要な成果:
- 100-160 Kの間には,水性および芳香性残留物のアンハーモニックな動きが活性化されました.
- 低温では,水素結合により,水性残基の動きが抑制された.
- 180~220Kで,水素結合の緩解と組み合わせた,水素性側鎖の水で活性化されたジャンプが明らかになった.
結論:
- タンパク質のダイナミクスは温度に依存し,異なる残留物のタイプには異なる行動を示します.
- サイトクロームP450カムの水性核は低温で"覚醒"し,さらに高温で水性表面が"覚醒"する.
- 水素化水と水素結合は,アミノ酸残基の温度依存のダイナミクスに大きな影響を与えます.
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