ディペプチド中のチロシルラジカルのスペクトル学的性質
Idelisa Ayala1, Kevin Range, Darrin York
1Department of Biochemistry, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108-1022, USA.
Journal of the American Chemical Society
|May 9, 2002
まとめ
レドックス活性型チロシンラジカルは,UV光分解を用いて生成された. ティロシルラジカルpiシステムとアミノ/アミド群の間の予期せぬ相互作用は,EPRとFT-IRスペクトロスコーピーを用いて観察されました.
科学分野:
- バイオケミストリー バイオケミストリー
- スペクトル顕微鏡検査です.
- タンパク質・ラジカル・ケミストリー タンパク質・ラジカル・ケミストリー
背景:
- レドックス活性型チロシン残基は,光システムIIのような酵素における電子移転に不可欠である.
- タンパク質における酸化還元活性アミノ酸の構造を研究することは,酵素機構を理解するために不可欠です.
- 磁気共振と振動スペクトロスコピーは,この調査の鍵となる技術です.
研究 の 目的:
- 紫外線光分解によって生成されるチロシルラジカルの構造を調査する.
- チロシルラジカルとペプチドの隣接するアミノまたはアミド群との相互作用を探求する.
- タンパク質ベースのチロシルラジカルを解釈するためのスペクトルベースを提供するため.
主な方法:
- 77 Kの紫外線光分解により,多結晶型チロシネートまたはダイペプチドからチロシル基を生成します.
- 電子パラマグネティック共振 (EPR) スペクトロスコーピーは,根幹構造を研究するために使用されます.
- 反応誘発フーリエ変換赤外線 (FT-IR) スペクトロスコーピーは,構造変化を検出するために,同位体ラベル ((13) C, (15) N) を付けています.
主要な成果:
- (13) C-ラベルされたチロシンから得られたEPRとFT-IR結果は,中性チロシル基の生成を確認した.
- (15) Nで標識されたサンプルにおける予期せぬ同位体シフトは,チロシル基のpiシステムとアミノ基間の相互作用を示した.
- ディペプチドからのスペクトルは,チロシル基とアミド結合の間の配列依存の相互作用を示した.
結論:
- スピン極化メカニズムは,チロシル基とアミノ/アミド群の相互作用を媒介し,NH力の定数の変化で検出される可能性が高い.
- 密度関数計算は,形状によって影響されるアミノおよびカルボキシラート群へのスピン密度デロカライゼーションをサポートします.
- これらの発見は,生物系における酸化還元活性チロシル基のスペクトル解釈を進めている.
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