モノアミン酸化酵素aにおける共振結合アニオンフラビン基の電子パラマグネティック共振による特徴化
Christopher W M Kay1, Hassane El Mkami, Gianluca Molla
1Department of Biology, University College London, UK. c.kay@ucl.ac.uk
Journal of the American Chemical Society
|November 30, 2007
まとめ
モノアミン酸化酵素 (MAO) AおよびB酵素は,チロシル基ではなく,アニオンフラビン基を含んでいます. マオ・ア・ア・マオ (マオア・ア・マオ) とは
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- 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:
- 部分的に減少したモノアミン酸化酵素 (MAO) A.A.に含まれる基幹種について,相反する報告がある.
- 以前の研究では,MAO Aはアニオンフラビンとチロシルラジカルの両方を含んでいると示唆されていたが,MAO Bはアニオンフラビンラジカルだけを示していた.
- MAO Aの発見に基づいて,MAOの修正された過激なメカニズムが提案されました.
研究 の 目的:
- MAO A.における報告された急性種の不一致を解決する.
- 高周波電子パラマグネティック共振 (EPR) を用いてMAOAの急進形態を調査する.
- MAO Aとd-アミノ酸酸化酵素 (DAAO) の根幹種と電子構造を比較する.
主な方法:
- 94 GHz (W帯) の連続波電子パラマグネティック共振 (EPR) がMAO A.を研究するために使用されました.
- パルス電子核二重共振 (ENDOR) のスペクトルは,MAO AとDAAOの9 GHz (X帯) で記録されました.
- 密度関数理論 (DFT) の計算を行い,超精細結合パターンを分析した.
主要な成果:
- MAOAとDAAOは,アニオンのフラビンラジカルしか含まれていないことが判明しました.
- MAOAとDAAOフラビンの間で明確な超精細結合パターンが観察され,C8alpha位置の違いによって説明されました.
- MAO Aは,C8alphaでシステインに共振的に結合するフラビンを持ち,DAAOは非共振的に結合するフラビンを持っています.
結論:
- MAO Aにおけるチロシルラジカルの存在は,この研究によって支持されませんでした.
- C8alphaでのフラビン結合の差異は,観測されたEPRスペクトルに影響します.
- DAAOに類似する直接ヒドリド転送機構は,MAO触媒のために提案されています.
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