ATPase SecAとタンパク質転位チャネルの複合体の構造
Jochen Zimmer1, Yunsun Nam, Tom A Rapoport
1Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Nature
|October 17, 2008
まとめ
バクテリアのタンパク質分泌物SecA ATPaseとSecY複合体は相互作用し,形状の変化を経験します. この構造的研究は,SecAがSecYと結合し,タンパク質が膜を横断して転移することを促進する方法を明らかにしています.
科学分野:
- 分子生物学は分子生物学である.
- 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:
- バクテリアのタンパク質分泌は,細胞機能と病原性にとって極めて重要です.
- SecA ATPaseとヘテロトリメリックSecY複合体は,細菌の分泌機構の重要な構成要素である.
- SecAとSecYの相互作用を理解することは,タンパク質転位機構の解読に不可欠です.
研究 の 目的:
- SecAがSecY複合体と結合した高解像度の結晶構造を決定する.
- バクテリアのタンパク質分泌に関与する構造変化と分子相互作用を解明する.
- SecYチャネルを通じたポリペプチド転位のメカニズムに関する洞察を提供するため.
主な方法:
- X線結晶学を用いて,Thermotoga maritima.からSecAおよびSecY複合体の構成要素の構造を取得しました.
- 結晶構造は4.5 Ångströmの解像度で決定されました.
- SecAとSecYの間の構造変化と結合インターフェースの分析.
主要な成果:
- 結晶構造は,1つのSecY複合体と結合した中間のATP水解状態にあるSecAの1つのコピーを明らかにします.
- 相互作用時にSecAとSecYの両方において重要な形状の変化が観察されました.
- SecAのポリペプチドクロスリンクドメインは,形状の変化を経験し,潜在的にクランプとして作用します.
- SecAの"2ヘリックス指"とクランプの動きは,SecYチャネルを通してポリペプチドの移動のための提案されたメカニズムです.
- SecAバインディングは,SecYサイドゲートで"ウィンドウ"を開き,プラグドメインを移動させます.
結論:
- この研究は,タンパク質分泌中のSecAとSecY複合体の相互作用の構造的基礎を提供します.
- 観察されたSecAとSecYの構成の変化は,基質の捕獲と転位に不可欠である.
- この構造情報は,細菌のタンパク質分泌経路と潜在的な薬物の標的に関する理解を深める.
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