CusA 流出ポンプの結晶構造は,メチオニン媒介の金属輸送を示唆しています
Feng Long1, Chih-Chia Su, Michael T Zimmermann
1Molecular, Cellular and Developmental Biology Interdepartmental Graduate Program, Iowa State University, Iowa 50011, USA.
Nature
|September 25, 2010
まとめ
CusAトランスポーターに関する構造的な洞察は,抵抗-結節-細胞分裂 (RND) 流出ポンプを使用して,グラム陰性細菌が銅や銀のような有毒な重金属をどのように輸出するかを明らかにします.
科学分野:
- 微生物学 微生物学とは
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- グラム陰性細菌はRND流出ポンプを使用して,有毒化合物を排出します.
- CusCBAシステムは,バイオシードCu (I) とAg (I) イオンを特異的にエクスプロードします.
- RND流出ポンプのHMEサブファミリーについては,これまでの構造データはありませんでした.
研究 の 目的:
- CusCBA流出システムの重要な構成要素であるCusAトランスポーターの構造を解明する.
- CusAによる重金属イオン結合とエクスポートのメカニズムを理解する.
- RND流出ポンプのHMEサブファミリーの構造的な洞察を提供するために.
主な方法:
- X線結晶学を用いて,CusA.の構造を決定した.
- アポ-CusAとCu (I) またはAg (I) に結合したCusAの構造が得られた.
- 遺伝子分析と輸送アッセイが行われました.
主要な成果:
- CusAの結晶構造は,裂け目領域のメチオニンクラスターによって形成された金属結合部位を明らかにしました.
- 周回プラズマ裂け目が金属結合時に閉ざされた状態から開いた状態に移行し,イオン輸出経路を示唆しています.
- 金属結合は,CusAの周回プラズマ領域と超膜領域における重要な構成変化を誘導する.
- CusAは,金属イオン結合と輸送に関与する複数のメチオニンペア/クラスターを有しています.
結論:
- CusAの構造は,RND流出ポンプのHMEサブファミリーに関する新しい洞察を提供します.
- メチオニンの複数の部位を含む金属イオン輸送のための段階的なシャトルメカニズムが提案されています.
- CusAは,バクテリアのサイトゾールから金属イオンを積極的に結合し,輸出する.
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