チオシアネートヒドローラゼの触媒活性化のための構造的基礎は,金属結合型システインの改変を含む
Takatoshi Arakawa1, Yoshiaki Kawano, Yoko Katayama
1Department of Biotechnology and Life Science, Graduate School of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
Journal of the American Chemical Society
|September 30, 2009
まとめ
チオシアネートヒドロラーゼ (SCNase) の活性度は,ガマCys133.3.のシステイン硫黄酸改変によって決定される. この変更は貯蔵中に発生し,再結合SCNaseの機能を強化します.
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- 構造生物学 構造生物学とは
背景:
- チオシアネートヒドローラゼ (SCNase) は,ニトリルヒドラゼ家族に属しています.
- 独特のノンコリンコバルトセンターと2つの翻訳後に改変されたシステインリガンド:システイン-スルフェン酸 (Cys-SO(H)) とシステイン-スルフィニナート (Cys-SO(2) ((-)) を特徴としています.
研究 の 目的:
- 再結合性SCNaseの成熟過程と活性決定因子を調査する.
- SCNaseの触媒機能におけるシステイン改変の役割を明らかにする.
主な方法:
- 貯蔵前のSCNaseと貯蔵後のSCNaseの結晶構造比較分析.
- 酵素活性とシステイン改変の程度との相関.
主要な成果:
- 部分的に成熟した再結合SCNaseは,貯蔵中に活性化を示した.
- gammaCys131のCys-SO(2)(-) 改変は貯蔵前に完了していた.
- ガンマCys133のCys-SO(H) 変異は貯蔵中に発生し,活性には極めて重要でした.
- ガンマCys133をさらに酸化してCys-SO (((2) ((-) に変換すると,SCNaseの活性が抑制される.
結論:
- gammaCys133のシステイン硫黄酸改変は,SCNaseの活性にとって重要である.
- 貯蔵中の酵素活性化は,gammaCys133.3.のインシット改変と関連しています.
- これらの変化を理解することで,ニトリルヒドラテース酵素機構の洞察が得られます.
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