Time-resolved cryo-EM visualizes ribosomal translocation with EF-G and GTP [preprint]
AuthorsCarbone, Christine E.
Loveland, Anna B.
Gamper, Jr., Howard
Korostelev, Andrei A.
UMass Chan AffiliationsGraduate School of Biomedical Sciences
Department of Biochemistry and Molecular Pharmacology
RNA Therapeutics Institute
Nucleic Acids, Nucleotides, and Nucleosides
MetadataShow full item record
AbstractDuring 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.
bioRxiv 2021.05.31.446434; doi: https://doi.org/10.1101/2021.05.31.446434. Link to preprint on bioRxiv.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/29827
This article is a preprint. Preprints are preliminary reports of work that have not been certified by peer review.
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Except where otherwise noted, this item's license is described as The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.