2D-EPRによって明らかにされた"ベース-fff"コブ ((II) アラミンおよび関連するコブ ((II) コリナートにおける軸性溶媒調整
Sabine Van Doorslaer1, Gunnar Jeschke, Boris Epel
1Laboratory of Physical Chemistry, ETH Hönggerberg, CH-8093 Zurich, Switzerland.
Journal of the American Chemical Society
|May 8, 2003
まとめ
コバルト (II) コーリネート,コブ (II) アラミン中介物と同様に,コエンザイムB12反応では,溶媒に依存した構造を示します. 先進的な EPR と ENDOR のテクニックは,溶媒の特性によって影響される軸結合と調整の変化を明らかにします.
科学分野:
- 協調化化学について
- バイオ・オーガニック化学 バイオ・オーガニック化学
- スペクトル顕微鏡検査です.
背景:
- コバルト (II) コリナートは,共酵素B12で触媒反応における重要な中間物質である.
- 溶液中のそれらの構造を理解することは,酵素機構の解明の鍵です.
- コバルト (II) エステルの溶解性は,コバルト (II) コーリナートに対する溶媒効果の制御研究を可能にします.
研究 の 目的:
- コバルト (II) コリナート,特にコバルト (II) エステルとコバルト (II) アラミン (B12r) の溶液構造を調査する.
- コバルトの調整状態 (軸結合) を決定するために,様々な溶媒中のコリナート (II) を用いる.
- コバルト (II) コーリネート構造に対する溶媒特性と相変化の影響を調査する.
主な方法:
- 連続波 (CW) とパルス電子パラマグネティック共振 (EPR) の組み合わせを用いた.
- 様々なマイクロ波周波数でENDOR (電子核二重共鳴) を使ったパルス.
- 支持されるデータ解釈は,密度関数理論 (DFT) 計算によるものです.
主要な成果:
- コブ・II・エステルとベースオフコブ・II・アラミン (B12r) の軸結合の明確な証拠を異なる溶媒で提供した.
- EPRパラメータ (g値,超精密結合) が溶媒結合の敏感な指標であることを実証した.
- メタノールのCob (II) エステルの温度に依存する構造変化が観察され,メタノールの相変化により100K以下で5〜6の調整から移行しました.
結論:
- 溶媒の特性により,コバルト (II) コーリネート (II) の調整構造が著しく影響を受ける.
- 溶液中のCob (II) エステルとベースオフB12rの調整行動は,それらの電子構造を反映している.
- 溶液の研究とタンパク質に埋め込まれたコファクターの比較は,溶媒の効果を慎重に検討する必要があります.
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