前処理ガラクトース酸化酵素における減少銅活性部位の構造:コファクターバイオゲネシスの1電子O2活性化のためのリガンドチューニング
Ryan E Cowley1, Jordi Cirera1, Munzarin F Qayyum1
1Department of Chemistry, Stanford University , Stanford, California 94305, United States.
Journal of the American Chemical Society
|September 15, 2016
まとめ
ギャラクトース酸化酵素 (GO) の生殖には,銅と酸素が含まれる. この研究は,銅が酸素の活性化と酵素機能のためのコファクター形成をどのように促進するか明らかにしています.
科学分野:
- 生物化学
- 酵素学
- バイオ有機化学
背景:
- グラクトース酸化酵素 (GO) は,基板の酸化に不可欠な銅に依存する酵素である.
- GOは独特のシステニル化チロシン (Cys-Tyr) 還元因子を利用しています.
- コファクター生物生成は,銅と酸素に依存する翻訳後のプロセスです.
研究 の 目的:
- GOにおけるCys-Tyrコファクター生物発生のメカニズムを解明する.
- バイオゲネシス中の酸素活性化における銅の役割を調査する.
- Cys-Tyrのクロスリンク形成を制御する構造的および電子的要因を理解する.
主な方法:
- Cu (I) 負荷のGOのアクティブサイト構造を決定するX線吸収近辺構造 (XANES) のスペクトロスコーピー.
- 詳細な構造分析のための拡張X線吸収微細構造 (EXAFS) スペクトロスコーピー.
- 反応機構をモデル化するための密度関数理論 (DFT) の計算.
主要な成果:
- 活性部位のチロシンは,銅の潜在性を低下させ,O2の1e-減少を促進します.
- その結果,システインから水素原子を抽出するために,Cu (II) 超酸化物の中間物質が活性化されます.
- 銅の調整はチロシン脱プロトン化とCys-Tyrクロスリンクの形成を促進する.
結論:
- 銅 (I) は1e-減少によるO2の活性化に重要な役割を果たします.
- 銅 (II) の中間物質は,交結形成のための基板 (システイン) の活性化に不可欠である.
- この研究は,GO Cys-Tyrコファクターの自己処理バイオゲネシスの主要なメカニズムのステップを明らかにしています.
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