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Updated: May 17, 2026

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Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
Published on: June 29, 2011
サイトクロームcにおけるHis26プロトネーションは,マイクロ秒間のβシート形成とヘム曝露を誘発する:アポトーシスへの影響
Gurusamy Balakrishnan1, Ying Hu, Thomas G Spiro
1Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
Journal of the American Chemical Society
|October 26, 2012
まとめ
サイトクロームcはベータシート構造に逆転的に展開し,そのヘム結合を破壊し,過酸化酵素の活性を得る. このプロセスは特定のプロトネーションイベントを含み,アポトーシスに関連したカルジオリピン過酸化に関連している可能性があります.
科学分野:
- バイオケミストリー バイオケミストリー
- タンパク質のダイナミクス
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- サイトクロームc (cyt c) は,アポトーシスの重要なタンパク質です.
- その過酸化酵素の活性性は,カルディオリピン過酸化と関連しています.
- 細胞の展開を理解することは,その生物学的役割にとって極めて重要です.
研究 の 目的:
- 低pHでシトクロームcが展開するメカニズムを調査する.
- 構造的変化と機能的変化との相関を特徴づける.
- 展開過程における特定の残留物や構造要素の役割を明らかにする.
主な方法:
- UV共鳴ラーマン (UVRR) スペクトロスコーピーは,二次構造を調査する.
- 温度ジャンプ (Tジャンプ) とUVRRを組み合わせて,時間解像度測定を行う.
- アロマティック残留物とヘムプロピオネート相互作用の分析.
主要な成果:
- pH 3で加熱すると,局所的で可逆的な細胞の展開が誘発されます.
- 展開はターンやヘリクスをベータシート構造に変換し,ランダムなコイルではありません.
- Met80-ヘム結合の破壊と芳香的残留物の方向の変化は,ヘム異位を示す.
- His26のプロトネーションは,Pro44との相互作用を妨害し,展開のカスケードを開始します.
- ベータシート形成とTrp59の方向転換の時間常数 (0.2,3.9,67 μs) を決定した.
結論:
- 展開メカニズムは,特定のプロトネーションと二次構造の変化を含み,ヘム露出と過酸化酵素の活性につながります.
- このメカニズムは,アポトーシス中のcytc媒介のカルジオリピン過酸化に関連している可能性があります.
- 40s Ωループは,His26-Pro44相互作用によって固定され,細胞の展開における重要な"折り畳み"として機能します.
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