Document Type
Article
Publication Date
12-13-2021
Abstract
During translation, a conserved GTPase elongation factor-EF-G in bacteria or eEF2 in eukaryotes-translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome•EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and EF-G by ~20 Å. An additional 4-Å translocation initiates EF-G dissociation from a transient ribosome state with highly swiveled 30S head. The structures visualize how nearly rigid EF-G rectifies inherent and spontaneous ribosomal dynamics into tRNA-mRNA translocation, whereas GTP hydrolysis and Pi release drive EF-G dissociation.
Recommended Citation
Carbone, Christine E; Loveland, Anna B; Gamper, Howard; Hou, Ya-Ming; Demo, Gabriel; and Korostelev, Andrei A, "Time-resolved cryo-EM visualizes ribosomal translocation with EF-G and GTP" (2021). Department of Biochemistry and Molecular Biology Faculty Papers. Paper 201.
https://jdc.jefferson.edu/bmpfp/201
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
PubMed ID
34903725
Language
English
Comments
This article is the author’s final published version in Nature Communications, Volume 12, Issue 1, December 2021, Article number 7236.
The published version is available at https://doi.org/10.1038/s41467-021-27415-0. Copyright © Carbone et al.