4V6T

Structure of the bacterial ribosome complexed by tmRNA-SmpB and EF-G during translocation and MLD-loading

これはPDB形式変換不可エントリーです。

4V6T の概要

• エントリーDOI: 10.2210/pdb4v6t/pdb
• EMDBエントリー: 5386
• 分子名称: 16S ribosomal RNA, 30S ribosomal protein S10, 30S ribosomal protein S11, ... (56 entities in total)
• 機能のキーワード: trans-translation, mld-loading, translocation, ribosome
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 56
• 化学式量合計: 2348613.11

構造登録者

Ramrath, D.J.F.,Yamamoto, H.,Rother, K.,Wittek, D.,Pech, M.,Mielke, T.,Loerke, J.,Scheerer, P.,Ivanov, P.,Teraoka, Y.,Shpanchenko, O.,Nierhaus, K.H.,Spahn, C.M.T. (登録日: 2012-01-27, 公開日: 2014-07-09, 最終更新日: 2024-02-28)

主引用文献

Ramrath, D.J.,Yamamoto, H.,Rother, K.,Wittek, D.,Pech, M.,Mielke, T.,Loerke, J.,Scheerer, P.,Ivanov, P.,Teraoka, Y.,Shpanchenko, O.,Nierhaus, K.H.,Spahn, C.M.
The complex of tmRNA-SmpB and EF-G on translocating ribosomes.
Nature, 485:526-529, 2012

PubMed Abstract: Bacterial ribosomes stalled at the 3' end of malfunctioning messenger RNAs can be rescued by transfer-messenger RNA (tmRNA)-mediated trans-translation. The SmpB protein forms a complex with the tmRNA, and the transfer-RNA-like domain (TLD) of the tmRNA then enters the A site of the ribosome. Subsequently, the TLD-SmpB module is translocated to the P site, a process that is facilitated by the elongation factor EF-G, and translation is switched to the mRNA-like domain (MLD) of the tmRNA. Accurate loading of the MLD into the mRNA path is an unusual initiation mechanism. Despite various snapshots of different ribosome-tmRNA complexes at low to intermediate resolution, it is unclear how the large, highly structured tmRNA is translocated and how the MLD is loaded. Here we present a cryo-electron microscopy reconstruction of a fusidic-acid-stalled ribosomal 70S-tmRNA-SmpB-EF-G complex (carrying both of the large ligands, that is, EF-G and tmRNA) at 8.3 Å resolution. This post-translocational intermediate (TI(POST)) presents the TLD-SmpB module in an intrasubunit ap/P hybrid site and a tRNA(fMet) in an intrasubunit pe/E hybrid site. Conformational changes in the ribosome and tmRNA occur in the intersubunit space and on the solvent side. The key underlying event is a unique extra-large swivel movement of the 30S head, which is crucial for both tmRNA-SmpB translocation and MLD loading, thereby coupling translocation to MLD loading. This mechanism exemplifies the versatile, dynamic nature of the ribosome, and it shows that the conformational modes of the ribosome that normally drive canonical translation can also be used in a modified form to facilitate more complex tasks in specialized non-canonical pathways.

PubMed: 22622583
DOI: 10.1038/nature11006

実験手法

ELECTRON MICROSCOPY (8.3 Å)