1つの水分子は,カチオニ化されたアルギニンズウィテリオン (zwitterion) を安定させます
Matthew F Bush1, James S Prell, Richard J Saykally
1Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA.
Journal of the American Chemical Society
|October 13, 2007
まとめ
リチア化されたアルギニンイオンに単一の水分子を加えると,ズウィテリオン型が安定し,その構造に影響を与えます. 金属イオンの大きさは,これらの水素化されたアミノ酸のクラスターの調整にも影響します.
科学分野:
- 物理化学 物理化学について
- コンピューティング・ケミストリー
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- 溶液中のアミノ酸の振る舞いを調査することは,生物学的プロセスを理解するために非常に重要です.
- アミノ酸のズウィテリオン性質は,それらの化学的性質と相互作用に根本的な役割を果たしています.
- 溶解効果,特に水分は,バイオモレクルの安定性と構造を大幅に変化させることができます.
研究 の 目的:
- リチアアルギニン,ナトリウムアルギニン,およびリチアアルギニンメチルエステルクラスターに対する単一水分子の水分化の構造的およびエネルギー効果を調査する.
- 金属イオン (リチウム対ナトリウム) と水分化のアルギニンのズウィテリオン状態への影響を決定する.
- 水酸化アルギニンクラスターにおける金属イオンの協調偏好 (NO対OO) を明らかにする.
主な方法:
- 赤外線アクションスペクトロスコピーは,イオン群の振動周波数と構造を調査するために使用されました.
- 計算化学,特にB3LYP/6-31++G**計算は,エネルギーと構造をモデル化するために使用されました.
- 安定した構成を特定するために,計算された構造と実験スペクトルの比較.
主要な成果:
- 単一水酸化リチアアルギニンは,その非ズウィテリオン未溶解の同位体とは異なり,25~32kJ/molで安定したズウィテリオン形態を好みます.
- 水素化されたリチア酸アルギニンとナトリウム酸アルギニンの実験スペクトルは,陽子化されたサイドチェーンを示し,類似性を示すが,リチア酸アルギニンメチルエステルは異なる.
- 金属イオン協調 (NO対OO) と,その結果生じるズウィテリオン構造は,金属イオンサイズと水分化によって影響を受けます.
結論:
- 単一の水分子による水分化は,リチアアルギニンのズウィテリオン型を安定させるのに十分である.
- 金属イオンの大きさ (Li+ vs. Na+) は,水性アルギニンクラスターにおける明確な調整偏好とズウィテリオン構造を決定する.
- 水分化は,金属イオン-アミノ酸の相互作用を弱めるが,強い水素結合を通じてズウィテリオン構造の安定性を高める.
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