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炭素一酸化物脱水素酵素の結晶構造は[Ni-4Fe-5S]クラスターを明らかにする
H Dobbek1, V Svetlitchnyi, L Gremer
1Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz 18a, D-82152 Martinsried, Germany. dobbek@biochem.mpg.de
Science (New York, N.Y.)
|August 18, 2001
まとめ
この研究は,無酸素細菌からのニッケルを含む一酸化炭素脱水素酵素 (CODH) の構造を明らかにしています. この発見は,CO酸化に不可欠な酵素の活性部位を明らかにした.
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:
- 炭素一酸化物脱水素酶 (CODH) 酵素は,炭素循環において不可欠である.
- ニッケルを含有するCODHは,無酸素微生物に多く存在します.
- CODHの構造を理解することは,CO酸化機構の解明の鍵です.
研究 の 目的:
- Carboxydothermus hydrogenoformans.からCODHの高解像度の結晶構造を決定する.
- 酵素内の活性部位を含む金属クラスターを特徴付ける.
主な方法:
- 1.6アングストームの解像度のX線結晶学.
- 酵素構造と金属クラスター組成の分析.
主要な成果:
- 還元されたCODHの結晶構造が解けました.
- 酵素には5つの金属クラスターが含まれています: キューバン型 [4Fe-4S]クラスター (B,B',D) と新しい非対称 [Ni-4Fe-5S]活性サイトクラスター (C,C').
- 活性部位にあるニッケルイオンは,4つの硫黄リガンドによって調整された正方形の平面幾何学を示している.
結論:
- 解かれた構造は,無酸素生命体におけるNiを含むCODHsのプロトタイプとして機能する.
- 新規の[Ni-4Fe-5S]クラスターは,CO酸化の可能性のある場所として特定されています.
- 構造的洞察は,CODHの機能と進化を理解するための基盤を提供します.
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