Ni,Feを含む一酸化炭素脱水原酶のシアン化物阻害の構造的基礎
Jae-Hun Jeoung1, Holger Dobbek
1Labor für Bioanorganische Chemie, Universität Bayreuth, 95447 Bayreuth, Germany.
Journal of the American Chemical Society
|July 9, 2009
まとめ
シアニドは,C-クラスターのニッケルイオンと結合することによって,一酸化炭素脱水酸化酵素 (CODHs) を阻害する. この結合は基板へのアクセスを阻害し,構造の変化を引き起こし,その抑制効果を説明します.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 酵素学 酵素学とは
背景:
- 一酸化炭素脱水酸化酵素 (CODHs) は,無酸素微生物における重要な酵素である.
- 彼らは,CO酸化を触媒する複雑なNi/Fe/S C-クラスターを含んでいます.
- シアン化物は,慢結合性CODHsの阻害剤として知られています.
研究 の 目的:
- CODHsにおけるシアン化物阻害の構造的基礎を解明する.
- 結合部位とシアン化物とC群との相互作用のメカニズムを決定する.
主な方法:
- カーボキシドテルムス (Carboxydothermus hydrogenoformans) から得られたCODH-IIのX線結晶学.
- 酵素・シアン化物複合体の高解像度構造分析 (1.36 Å)
主要な成果:
- シアニドは,Cクラスター内のニッケルイオン上のオープンな調整部位と結合する.
- この結合は,ニッケールの正方形平面幾何学を完了する.
- 鉄に近い水/ヒドロキソリガンドは失われ,鉄はニッケルに近づく.
結論:
- シアン酸は,ニッケルとのCO結合を阻害することによって,CODHを競争的に抑制する.
- ゆっくり結合する阻害は,鉄に結合した水/ヒドロキソリガンドの喪失を含むタンパク質構成の変化によるものです.
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