アロマティックアミノ酸を含む様々なタイプの水素結合の比較
Steve Scheiner1, Tapas Kar, Jayasree Pattanayak
1Department of Chemistry & Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
Journal of the American Chemical Society
|October 31, 2002
まとめ
ヒスティジンやトリプトファンのような芳香性アミノ酸は,強い水素結合を形成する. これらの相互作用は,従来の,OH..pi,およびCH..O結合を含む,タンパク質の構造を安定させるために不可欠です.
科学分野:
- バイオケミストリー バイオケミストリー
- コンピューティング・ケミストリー
- 構造生物学 構造生物学とは
背景:
- アミノ酸のサイドチェーンは,タンパク質の構造と機能において重要な役割を果たします.
- 水素結合は,バイオ分子における重要な非共性相互作用である.
- アロマティックアミノ酸 (フェニララニン,チロシン,トリプトファン,ヒスティジン) は,ユニークな電子特性を持っています.
研究 の 目的:
- アロマティックアミノ酸側鎖の水素結合能力を比較する.
- 異なるタイプの水素結合を調査するために:従来の,OH..pi,およびCH..O.
- これらの相互作用の相対的な強さと,タンパク質の安定性への貢献を決定する.
主な方法:
- 相互作用をモデル化するために,ab initio計算を利用する.
- アミノ酸をその核の芳香構造で表す:ベンゼン,フェノール,インドール,イミダゾール.
- 様々なドナー-受容体ペアの水素結合エネルギーを分析する.
主要な成果:
- ヒスティジンとチロシンは,最も強い従来の水素結合 (例えば,OH..O,OH..N) を形成します.
- トリプトファンは最も強いOH..pi相互作用を示し,ヒスティジン,チロシン,フェニララリンが次いでいます.
- CH..Oの相互作用はヒスティジンとトリプトファンにとって,特にプロトン化形態では有意である.
結論:
- アロマティックアミノ酸によって形成される水素結合の種類と強さは大きく異なります.
- ヒスティジンとトリプトファンは,多様な水素結合を通じてタンパク質の構造を安定させる上で特に重要な役割を果たします.
- ヒスティジンのプロトネーションは,ヒステジンの水素結合能力を高め,タンパク質のダイナミクスに影響を与えます.
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