コビナミドBのモデルにおける超長軸性Co (II) -N結合の存在を,電子パラ磁気共振スペクトロスコーピーを用いて評価する
J S Trommel1, K Warncke, L G Marzilli
1Department of Physics, Emory University, Atlanta, Georgia 30322, USA.
Journal of the American Chemical Society
|July 18, 2001
まとめ
この研究は,EPRスペクトロスコピーとビタミンB12に関する理論の間の不一致を解決します.
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・オーガニック化学 バイオ・オーガニック化学
背景:
- ビタミンB12共酵素におけるコバルト-軸性窒素リガンド結合長さのタンパク質制御は,反応性を調節するように提案されています.
- 超長期のCo-N結合は,トランス-コバルト-炭素結合の同解分裂を促進する可能性があります.
研究 の 目的:
- B12ホロ酵素における超長いCo-N結合に関するX線結晶学的発見を,EPRスペクトロスコーピーを用いて明らかにする.
- コビナミドアダクトに関するEPR理論と実験結果の間の明らかな矛盾を解決するために.
主な方法:
- 研究されたコビナミド (Co) コビナミド (Co) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Co) コビナミド (Co) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi)) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi)) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi)) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi) コビナミド (Cbi))
- 2-ピコリンを浄化し,リガンドの不純物を除去するために,新しいCo (((III)) -アフィニティ蒸留を使用しました.
- 様々な代用ピリジンとCo(II) Cbi(+) の結合選択性を調査した.
主要な成果:
- 理論と一致して,4-置換ピリジンの基本性を減少させながら,Co (((II) ハイパーファインの分裂が線形的に増加することを発見しました.
- 浄化された2-ピコリンがCo ((II) Cbi (((+)) とアダクトを形成しないことが示され,以前の発見を反証した.
- コリンリングからのステリック阻害を,Co (II) Cbi (II) Cbi (+) 選択結合の重要な要因として特定した.
結論:
- EPRの実験と理論の間の明らかな対立は解決された.
- 酵素結合ビタミンB12コファクターにおけるCo-N軸結合は,おそらく超長ではない.
- Co ((II) Cbi ((+) は,阻害されない窒素ドナーリガンドの選択的結合剤として作用する.
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