6R7L

Ribosome-bound SecYEG translocon in a nanodisc

6R7L の概要

• エントリーDOI: 10.2210/pdb6r7l/pdb
• EMDBエントリー: 4743
• 分子名称: SecG, SecE,Protein translocase subunit SecE,Protein translocase subunit SecE,Protein translocase subunit SecE, Protein translocase subunit SecY (3 entities in total)
• 機能のキーワード: monomeric translocon, nanodisc, insertion intermediate, membrane protein
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 61323.82

構造登録者

Kater, L.,Beckmann, R.,Kedrov, A. (登録日: 2019-03-29, 公開日: 2019-08-07, 最終更新日: 2024-05-22)

主引用文献

Kater, L.,Frieg, B.,Berninghausen, O.,Gohlke, H.,Beckmann, R.,Kedrov, A.
Partially inserted nascent chain unzips the lateral gate of the Sec translocon.
Embo Rep., 20:e48191-e48191, 2019

PubMed Abstract: The Sec translocon provides the lipid bilayer entry for ribosome-bound nascent chains and thus facilitates membrane protein biogenesis. Despite the appreciated role of the native environment in the translocon:ribosome assembly, structural information on the complex in the lipid membrane is scarce. Here, we present a cryo-electron microscopy-based structure of bacterial translocon SecYEG in lipid nanodiscs and elucidate an early intermediate state upon insertion of the FtsQ anchor domain. Insertion of the short nascent chain causes initial displacements within the lateral gate of the translocon, where α-helices 2b, 7, and 8 tilt within the membrane core to "unzip" the gate at the cytoplasmic side. Molecular dynamics simulations demonstrate that the conformational change is reversed in the absence of the ribosome, and suggest that the accessory α-helices of SecE subunit modulate the lateral gate conformation. Site-specific cross-linking validates that the FtsQ nascent chain passes the lateral gate upon insertion. The structure and the biochemical data suggest that the partially inserted nascent chain remains highly flexible until it acquires the transmembrane topology.

PubMed: 31379073
DOI: 10.15252/embr.201948191

実験手法

ELECTRON MICROSCOPY (6 Å)