光活性黄色タンパク質の低バリア水素結合:水晶と溶液に欠けている真空人工物
Timo Graen1, Ludger Inhester2, Maike Clemens1
1Max Planck Institute for Biophysical Chemistry , Am Faßberg 11, 37077 Göttingen, Germany.
Journal of the American Chemical Society
|December 15, 2016
まとめ
この研究では,光活性黄色タンパク質 (PYP) の低バリア水素結合 (LBHB) の存在に異議を唱え,核量子効果のない実験データに適した代替モデルを提案しています.
科学分野:
- バイオ物理学
- 構造生物学
- コンピュータ化学
背景:
- 光活性黄色タンパク質 (PYP) の低バリア水素結合 (LBHB) の存在は議論されている.
- 以前の研究では,中性Arg52の残留がLBHBの形成を誘発すると示唆されていました.
研究 の 目的:
- 既存のデータと一致する PYPにおける LBHB 形成の代替モデルを提示する.
- LBHBの結晶環境とArg52プロトネーション状態の役割を調査する.
主な方法:
- ニュートロンの屈折構造因子の分析
- 結晶,溶液,真空条件下での分子動力学 (MD) シミュレーション
- 3D核均衡密度の計算
主要な成果:
- 原子核量子効果のない,陽子化されたArg52の水素結合長さの増加を説明する代替モデルが提案されている.
- シミュレーションによると 結晶環境はArg52の水素結合を安定させ pKaの上昇を予測しています
- 真空計算は,LBHBと大きな1H NMR化学シフトを好むアーティファクトを導入します.
結論:
- PYPは真空環境ではなく 結晶環境が正確に説明します
- 提案されたモデルは実験データを説明し,以前の解釈の異常を示唆しています.
- PYPにおけるLBHBは,特定の環境要因がない場合,生理学的条件下では起こりそうにない.
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