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ピロコクス ・ フリオサス の [NiFe] - 水素酸 は 新しい 種 の 酸素 耐性 を 示し て い ます
Patrick Kwan1, Chelsea L McIntosh1, David P Jennings1
1Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287, United States.
Journal of the American Chemical Society
|October 6, 2015
まとめ
この研究は,酸素が特定の酵素であるPyrococcus furiosus hydrogenase I (PfSHI) にどのように影響するかを特徴づけています. PfSHIは,特に高温で,他の水酸化物とは異なり,驚くべき酸素耐性を示しています.
科学分野:
- 生物化学
- 酵素学
- バイオエネルギー
背景:
- [NiFe]-ヒドロゲネーゼは水素代謝に不可欠な酵素である.
- 溶解性グループ3の[NiFe]-ヒドロゲナーゼは,PfSHIのように酸素耐性があることが知られているが,グループ1の酵素に含まれる保護性 [4Fe3S]クラスターがない.
- 酸素がこれらの酵素に与える影響を理解することは バイオテクノロジーの応用に不可欠です
研究 の 目的:
- Pyrococcus furiosus (PfSHI) の溶解性グループ3 [NiFe]-ヒドロゲナーゼの酸素耐性を電気化学的に特徴付ける.
- 酸素曝露に対する PfSHI の反応の温度依存性を調べる.
- この酵素クラスにおける新分類 ("酸素耐性") と酸素耐性のメカニズムモデルを提案する.
主な方法:
- クロノアンペロメトリーは,水素酸化活動を測定するために使用されました.
- 酸素濃度や温度が変化した際に,酵素の活性が短期間または長期にわたって評価された.
- 不活性状態を特定するために,再活性化運動を分析した.
主要な成果:
- PfSHIは酸素耐性を示し,幅広い温度 (15- 80 °C) で短い酸素曝露後に活動を保持します.
- 酸素の曝露は少なくとも2つ,そして潜在的に3つの異なる不活性状態の形成につながります.
- 持続的な酸素被曝に対する酵素の耐性は,温度に依存しており,80°Cで重要な活性が維持され,25°Cで失われます.
- 短期間の無効化による再活性化は迅速 (<150秒),長期間の無効化による再活性化は遅い (数十分).
結論:
- PfSHIは"酸素耐性"として提案されており",酸素耐性"のグループ1の水酸化物とは異なる新しいカテゴリーである.
- [4Fe3S]クラスタとは独立して,溶解性グループ3[NiFe]-ヒドロゲナーゼにおける酸素耐性の新しいメカニズムが提案されている.
- [NiFe]ヒドロゲネーゼの酸素耐性および不活性化経路の理解を修正する必要がある.
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