エネルギー変換におけるトン複合体の役割に関する構造的洞察

Hervé Celia^1,2, Nicholas Noinaj³, Stanislav D Zakharov³

¹Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, 13402 Marseille Cedex 20, France.

Nature

|September 23, 2016

まとめ

この研究は,栄養素の輸入に不可欠なグラム陰性細菌のトン複合体の構造を明らかにしています. 研究者達はその構成要素と陽子のエネルギーを輸送する方法を明らかにしました

科学分野:

微生物学
構造生物学
生物化学

背景:

グラム陰性細菌は栄養素を吸収するために外側膜のトランスポーターを利用します
これらのトランスポーターは,内膜トン複合体 (TonB,ExbB,ExbD) によって動いています.
トン・コンプレックスは陽子の運動力を結合して栄養素を外側膜に運びます

研究の目的:

エシェリキア・コロイのトン複合体を構造的に特徴づける.
トン複合体のステキオメトリーとサブユニットの配置を決定する.
トン複合体のエネルギー伝導機構を調査する

主な方法:

X線結晶学
電子顕微鏡
二重電子共鳴光譜 (DEER)
クロスリンク
電気生理学

主要な成果:

トン複合ステキオメトリは,ExbBのペンタマー,ExbDのダイマー,および少なくとも1つのTonBとして決定された.
構造データは,TonB,ExbB,ExbDのサブユニットの配置を明らかにしました.
電気生理学では,トンサブコンプレックスはpHに敏感なカチオン選択チャネルを形成することを示した.

結論:

この研究は,細菌のトン複合体の最初の構造的特徴を明らかにした.
この発見はトン・コンプレックスがエネルギー伝達のために陽子の運動力をどのように利用するかについての洞察を提供しています
この研究は,グラム陰性細菌の栄養素輸送メカニズムに関する理解を深めています

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