プラストシアニンの活性部位構造と電子移転反応性
Katsuko Sato1, Takamitsu Kohzuma, Christopher Dennison
1Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK.
Journal of the American Chemical Society
|February 20, 2003
まとめ
銅プラストシアニンの活性部位構造 (PCu) は,
科学分野:
- バイオケミストリー バイオケミストリー
- バイオフィジックス 生物物理学
- 進化生物学の進化生物学について
背景:
- 銅プラストシアニン (PCu) は,様々な生物における電子伝送に不可欠な酸化還元金属タンパク質である.
- PCuのアクティブサイト構造は,進化を通して保存されています.
- 電子移転 (ET) 反応性は,タンパク質構造と表面電荷分布によって影響を受けます.
研究 の 目的:
- 様々な進化的起源のPCuのアクティブサイト構造と電子自己交換 (ESE) 反応性を調査する.
- 構造的特徴,特に表面酸性残留をET率と相関させる.
- PCu構造の進化的保存とその機能への影響を理解する.
主な方法:
- パラマグネティック (1) H NMRスペクトロスコピーは,PCu's.の活性部位構造を分析するために使用されました.
- 電子の自己交換反応 (ESE) を用いて,電子伝送率を測定した.
- 充電された残留物とプロトネーションの影響を評価するために,異なるイオン強度とpHで研究が行われました.
主要な成果:
- PCuのアクティブサイト構造とスピン密度分布は,植物,藻類,シアノバクテリアで高度に保存されています.
- ESE速度定数は,酸性表面残留物の存在と分布と相関して,著しく変化します.
- より高いイオン強度と酸性残留物の除去は,ESE率を高め,比較可能な固有のET能力を示唆しています.
- PCu ((I) でのHis87のプロトネーションは,酸性パッチの影響を最小限に抑えた場合,ESE率を低下させます.
結論:
- PCuの保存されたアクティブサイト構造は,多様な種間の電子伝送におけるその役割を容易にします.
- 表面の電荷分布,特に酸性残留は,ET反応性を調節する上で重要な役割を果たします.
- PCuの進化の軌道は,ET効率を微調整するために表面特性を適応させながら,構造的整合性を維持してきました.
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