エントロピーは,陽子化されたプロリンに付着した水分子をC端からN端へと駆動する
James S Prell1, Thiago C Correra, Terrence M Chang
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|October 5, 2010
まとめ
陽子化されたプロリン水分化は,温度上昇とともにカルボキシル酸からN末端に移行する. 陽子プロリンにおけるこの温度に依存する結合偏好は,異なるエンタルピックおよびエントロピック要因によって引き起こされます.
科学分野:
- 化学物理 化学物理
- スペクトル顕微鏡検査です.
- アミノ酸化学 アミノ酸化学
背景:
- 陽子化されたアミノ酸は複雑な水分化構造を示します.
- サイト固有の水の相互作用を理解することは,生物分子溶解研究にとって極めて重要です.
研究 の 目的:
- プロトネートプロリンの温度依存の水分化部位の偏好を調査する.
- 水がプロトン化されたプロリンと結合する背後にある熱力学的原動力を解明する.
主な方法:
- 赤外線光解離光譜法 (IRPD) を用いて,水分化構造を調べました.
- 温度の関数としての水分化同位体の運動分析が行われました.
- ヴァント・ホフプロットは,熱力学的パラメータを決定するために,運動データから生成されました.
主要な成果:
- 単一の水素化,プロトン化プロリンは,低温でカルボキシル酸部位を好むことを示している.
- より高い温度では,水は陽子化されたN端に優先的に結合します.
- C端の結合はエンタルピー的に好ましい (4.26.4 kJ/mol),N端の結合はエントロピー的に好ましい (3143 J/mol K)).
結論:
- プロトネートプロリンの水分化部位は温度に敏感であり,C端からN端に切り替わります.
- エンタルピーとエントロピーの差異は,観測された温度に依存する水分化の好みを支配する.
- 水分子の回転に対する計算されたバリアは,C端のより高いバリアを示唆し,結合に影響を与える.
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