DMSO還元酵素の結晶構造:モリボドプテリンの調整のレドックス関連変化
H Schindelin1, C Kisker, J Hilton
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.
Science (New York, N.Y.)
|June 14, 1996
まとめ
気候調節に不可欠なディメチル硫酸化物 (DMSO) 還元酵素が構造的に分析されました. そのモリブデンコファクターは明確な協調性を示し,基板の還元機構の洞察を明らかにします.
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
- 環境科学 環境科学
背景:
- ディメチル硫酸化物 (DMSO) 還元酵素は,気候に影響を与えるガスであるディメチル硫化物の放出に関与するモリブド酵素です.
- ディメチル硫化物は,雲の核形成と地球的な気候の調節に作用する.
- 酵素の構造を理解することは,その触媒機構の解明の鍵です.
研究 の 目的:
- Rhodobacter sphaeroidesからのDMSO還元酵素の結晶構造を決定する.
- 異なる酸化還元状態におけるモリブデンコファクターの調整を調査する.
- 基板結合と還元のためのメカニズムを提案する.
主な方法:
- 酵素の構造を決定するために,X線結晶学を用いた.
- 構造分析は,モリブデン共同因子とその調整環境に焦点を当てました.
- 配列の比較は,関連するオックストランスフェラーゼ酵素と実施した.
主要な成果:
- 結晶構造は,2つのモリボドプテリンのグアニン・ディヌクレオチドとモノオキソモリブデン共同因子を明らかにした.
- ディチオレン群によるモリブデンの非対称な調整が観察されました.
- 酸化状態 (Mo(VI)) と還元状態 (Mo(IV)) の間の異なるプテリン調整が特定されました.
- Ser147のサイドチェーン酸素は一貫してモリブデンに調整されます.
結論:
- プテリン調整の観察された変化は,基質結合と還元のためのメカニズムを示唆しています.
- DMSO還元酵素は,他のモリボドプテリン・グアニン・ディヌクレオチドを含むオックストランスフェラーゼと構造的および活性部位の類似性を共有しています.
- この構造的洞察は,バイオジオケミカルサイクルと気候規制における微生物の役割を理解するのに役立ちます.
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