0型銅タンパク質の電子構造に対する外球からの寄与
Kyle M Lancaster1, María-Eugenia Zaballa, Stephen Sproules
1California Institute of Technology, Pasadena, California 91125, United States. kml236@cornell.edu
Journal of the American Chemical Society
|May 9, 2012
まとめ
研究者らはタンパク質に新しい"タイプ0"の銅部位を発見し,生物無機法典に挑戦した. これらの部位は,チオ酸塩の調整が欠けていて,ユニークな電子構造と電子伝送特性を表しています.
科学分野:
- バイオ・オーガニック化学
- バイオフィジックス 生物物理学
- プロテイン工学は,タンパク質の
背景:
- 確立された生物無機法典は,活性部位のチオラート調整が1型銅タンパク質の急速な電子移転 (ET) に不可欠であると仮定しています.
- 最近の発見は,銅ETサイトは,チオラート結合なしで設計することができ",タイプゼロ"サイトと呼ばれることを示しています.
研究 の 目的:
- Pseudomonas aeruginosa azurinの変種におけるタイプ0銅部位の構造的および電子的特性を調査する.
- 0型サイトの電子構造を,ワイルド型 (1型) と2型銅センターと比較する.
主な方法:
- 多周波電子パラマグネティック共振 (EPR),磁気円形二重化 (MCD),核磁気共振 (NMR) のスペクトロスコーピー.
- 密度関数理論 (DFT) とスペクトロスコピー指向型構成相互作用 (SORCI) の計算.
- 量子力学/分子力学 (QM/MM) シミュレーション.
主要な成果:
- Pseudomonas aeruginosa azurinの変種におけるタイプ0銅センターは,野生型のタイプ1センターと実質的に同一のリガンドフィールドを示しています.
- 1型および2型タンパク質と比較して,タイプ0センターでは,強化されたOドナー共性および減少したNドナー共性が観察されました.
- タイプ0とタイプ2のサイトの電子構造は,外界圏の水素結合によって調節されるカルボキシラートリガンドの方向性と調整によって強く影響を受けます.
結論:
- タイプ0の銅部位は,電子伝送特性を調節するための従来のタイプ1の部位に有効な代替案です.
- 水素結合によって影響されるカルボキシラートリガンドの調整と指向は,非チオラート銅の中心における電子構造の決定的決定因子である.
- この研究は,銅タンパク質の活性部位の理解を拡大し,タンパク質工学の新たな道を開きます.
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