- EMDB-10074: SecA in complex with ribosome nascent chain -
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基本情報
登録情報
データベース: EMDB / ID: EMD-10074
タイトル
SecA in complex with ribosome nascent chain
マップデータ
SecA bound to translating ribosome (with focused refined)
試料
複合体: ribosome nascent chain in complex with SecA
タンパク質・ペプチド: SecA
機能・相同性
機能・相同性情報
cell envelope Sec protein transport complex / protein-secreting ATPase / intracellular protein transmembrane transport / protein transport by the Sec complex / protein import / protein targeting / ATP binding / metal ion binding / plasma membrane / cytosol 類似検索 - 分子機能
National Institutes of Health/National Center for Research Resources
米国
引用
ジャーナル: Nat Struct Mol Biol / 年: 2019 タイトル: The molecular mechanism of cotranslational membrane protein recognition and targeting by SecA. 著者: Shuai Wang / Ahmad Jomaa / Mateusz Jaskolowski / Chien-I Yang / Nenad Ban / Shu-Ou Shan / 要旨: Cotranslational protein targeting is a conserved process for membrane protein biogenesis. In Escherichia coli, the essential ATPase SecA was found to cotranslationally target a subset of nascent ...Cotranslational protein targeting is a conserved process for membrane protein biogenesis. In Escherichia coli, the essential ATPase SecA was found to cotranslationally target a subset of nascent membrane proteins to the SecYEG translocase at the plasma membrane. The molecular mechanism of this pathway remains unclear. Here we use biochemical and cryoelectron microscopy analyses to show that the amino-terminal amphipathic helix of SecA and the ribosomal protein uL23 form a composite binding site for the transmembrane domain (TMD) on the nascent protein. This binding mode further enables recognition of charged residues flanking the nascent TMD and thus explains the specificity of SecA recognition. Finally, we show that membrane-embedded SecYEG promotes handover of the translating ribosome from SecA to the translocase via a concerted mechanism. Our work provides a molecular description of the SecA-mediated cotranslational targeting pathway and demonstrates an unprecedented role of the ribosome in shielding nascent TMDs.