ホモディメア酵素の基板ベースのアロステル調節
Pedram Mehrabi1,2,3, Christopher Di Pietrantonio4, Tae Hun Kim4,5
1Department of Medical Biophysics , University of Toronto , Toronto , Ontario M5G 1L7 , Canada.
Journal of the American Chemical Society
|June 13, 2019
まとめ
フッ素酸脱塩酵素は酵素ダイナミクスを触媒として用いる. 高濃度の基質は,この酵素を阻害し,ダイナミクスを抑制し,特定の変異は阻害をなくすが,触媒速度を低下させ,アロステル調節の重要性を明らかにする.
科学分野:
- 生物化学
- 酵素学
- 構造生物学
背景:
- 多くの酵素は半分の反応性を示し,一度に1つの活性サイトのみが機能する.
- ホモディメア酵素であるフッ素酸脱塩酵素は,原体活性と動態を調節するために基板結合を利用する.
研究 の 目的:
- フロロアセタートデハロゲネーゼの触媒におけるインタープロトメアダイナミクスの役割を調査する.
- 高い基質濃度での抑制メカニズムとアロステルポケットの機能を解明する.
主な方法:
- 剛性に基づくアロステリック伝達理論
- 核磁共振 (NMR) スペクトロスコーピー
- 機能検査
主要な成果:
- 高濃度の基質は,第2基質結合を引き起こし,プロトメア間の動態を抑制し,触媒を抑制する.
- 変異 (K152I) は第2部位結合と抑制を廃止するが,最大触媒速度を低下させ,アロステルポケットの触媒作用を示している.
- 外側のポケットは基板を溶解し,活性部位への移動を容易にし,アロステル管として作用する.
結論:
- アロステルネットワークによって調節される酵素の動態は,フッ素酸塩脱酸化酵素の機能にとって極めて重要です.
- 高濃度での第二基板結合は,これらの本質的なダイナミクスを破壊することによって触媒を阻害します.
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