海洋バクテリアに広く存在しているダイメチルスルフォニオプロピオネートの吸収のための新しい経路
Chris R Reisch1, Melissa J Stoudemayer, Vanessa A Varaljay
1Department of Microbiology, University of Georgia, Athens, Georgia 30602, USA.
Nature
|May 13, 2011
まとめ
海洋バクテリアは,新しい酵素経路を利用してディメチルスルフォニオプロピオネート (DMSP) を処理し,メチルマーカプトプロピオネート (MMPA) を同化してメタネチオール (MeSH) を生成します. この経路は,海洋細菌プランクトンに広く存在しています.
科学分野:
- 海洋微生物生態学について
- バイオジオケミストリー バイオジオケミストリー
- 酵素学 酵素学とは
背景:
- ディメチルスルフォニオプロピオネート (DMSP) は,海洋表面水中の重要な炭素と硫黄化合物であり,植物プランクトンによって生成されます.
- 海洋細菌は,脱メチル化/脱メチオ化によってDMSPを処理し,メタネチオール (MeSH) を放出し,還元硫黄を吸収する.
- メチルマーカプトプロピオネート (MMPA) の吸収のための特定の酵素と生化学的経路は20年以上も未知でした.
研究 の 目的:
- DMSPの分解からメチルマーカプトプロピオネート (MMPA) の同化に起因する生化学的経路と酵素を特定する.
- 海洋環境における低硫黄吸収の微生物メカニズムを解明する.
主な方法:
- 遺伝子および酵素分析を用いた生化学経路の再構築.
- 新種のコエンザイムA (CoA) 誘導体の識別:3-メチルマーキャプトプロピオニル-CoA (MMPA-CoA) とメチルチオアクリロイル-CoA (MTA-CoA).
- バクテリア株 (例えば,Ruegeria pomeroyi DSS-3,Pelagibacter ubique) と海洋細菌プランクトンのゲノムおよびメタゲノム解析.
主要な成果:
- 脂肪酸β酸化に関連する3つの新しい酵素が,MMPAの同化経路として特定されました.
- この経路では,重要な中間物質としてMMPA-CoAとMTA-CoAが形成されます.
- この経路は,ルゲリア・ポメロイ (Ruegeria pomeroyi) のMMPA吸収とMeSH生成に不可欠であり,海洋細菌プランクトンに広く存在しています.
結論:
- 脂肪酸 β-酸化酵素を含む以前未知の微生物経路は,DMSP由来化合物であるMMPAを同化します.
- この経路は,海洋異質栄養生物による硫黄と炭素の吸収に極めて重要です.
- 特定された経路は,海洋表面水中の低硫黄循環のための重要な経路を表しています.
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