呼吸連鎖の電子を用いて細菌の封筒内の酸化タンパク質を修復する

Alexandra Gennaris^1,2,3, Benjamin Ezraty⁴, Camille Henry⁴

¹WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium.

Nature

|December 8, 2015

まとめ

研究者はMsrPQという細菌の酵素システムを発見し細胞の膜内のタンパク質に酸化したメチオニンを修復しますこのシステムは反応性酸素と塩素から細菌を保護し宿主の防御に対して生存に不可欠です

科学分野:

微生物学
生物化学
細胞生物学

背景:

反応性酸素と塩素はタンパク質を含む細胞の成分を損傷します
タンパク質におけるメチオニンの残留物の酸化は,生物学的活性喪失につながります.
メチオニン硫酸還元酵素 (Msrs) は,様々な細胞部位で酸化したメチオニンを修復する.

研究の目的:

酸化メチオニンを修復するバクテリアの細胞封筒内の酵素系を特定し特徴づけること.
この新しい酵素システムのメカニズムと機能を理解するために

主な方法:

酵素の識別と特徴づけ
酸化ストレス下での酵素活性分析
生体内の酵素機能を評価するための遺伝子操作
基質の特異性と電子移転メカニズムを決定する生化学的測定.

主要な成果:

MsrPQ (モリブド酵素) とMsrQ (ヘム結合タンパク質) を含むMsrPQシステムの識別
MsrPQはグラム陰性細菌に保存され,ヒポクロース酸によって誘発されます.
MsrPQは封筒の整合性を維持し,メチオニンの酸化から周回プラズマタンパク質を救う.
このシステムは,呼吸連鎖からの電子を利用し,メチオニン硫化物のRとS二ステロエーマーの両方を減少させます.

結論:

MsrPQは新種の酵素システムで,細菌の細胞膜を酸化による損傷から守ります.
このシステムは,周回血質に還元物質を輸入するためのユニークなメカニズムを使用します.
MsrPQの非ステレオ特異性は,より広範な保護的役割とeukaryoticシステムにおける潜在的なパラレルを示唆する.

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