NMR化学シフトの乱れから決定されたタンパク質の介電常数
Predrag Kukic1, Damien Farrell, Lawrence P McIntosh
1School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, UCD Conway Institute, University College Dublin , Belfield, Dublin 4, Ireland.
Journal of the American Chemical Society
|October 16, 2013
まとめ
この研究では,NMR化学シフトの干渉を用いた電気場を測定することによって,タンパク質の最適な介電定数を決定しました. この発見は,精密な静電計算に不可欠なタンパク質の介電常数に対する新しい内在的な値を示唆しています.
科学分野:
- バイオフィジックス 生物物理学
- 構造生物学 構造生物学とは
- コンピューティング・ケミストリー
背景:
- 精密な静電計算は,タンパク質の構造と機能の関係を理解するために不可欠です.
- タンパク質モデルの適切な介電常数 (ε(eff) と ε(p)) に関して,長年にわたる議論が存在しています.
- 現在の介電常数値は,経験的に,間接的に測定され,その一般的な適用性を制限します.
研究 の 目的:
- タンパク質の最適な介電常数 (ε(eff) と ε(p)) を決定する.
- NMR化学シフト扰乱 (CSP) を使用してタンパク質の電場を直接測定する.
- 静電モデリングのためのより正確で転送可能な介電定数を確立する.
主な方法:
- 電場を特徴づけるために,14種類のタンパク質にわたってCSPを測定した.
- コロンブ定理を適用し,CSPと介電常数とを相関させた.
- インタフェース分析のためのPoisson-Boltzmann計算を利用した有限差.
主要な成果:
- 最適な ε (((eff) は3から13の範囲で,クーロン法を使用すると平均は6.5でした.
- プアソン・ボルツマン計算による水とタンパク質のインターフェイスを考慮すると,最適な ε (p) は 3 (範囲 2-5) であることが判明しました.
- 決定された3の ε (p) は,熱力学計算に使用されるより高い値とは異なり,タンパク質粉末測定値と一致しています.
結論:
- 折りたたまれたタンパク質の導出ダイエレクトリック定数3は,おそらく内在的で移転可能であり,電場を正確に反映します.
- この値は,熱力学パラメータに基づくモデルで使用される値と大きく異なる.
- この発見は,タンパク質の構造に基づく静電計算のためのより堅固な基盤を提供します.
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