7SSN

Pre translocation 70S ribosome with A/P* and P/E tRNA (Structure II-B)

This is a non-PDB format compatible entry.

Summary for 7SSN

• Entry DOI: 10.2210/pdb7ssn/pdb
• EMDB information: 25405 25407 25409 25410 25411 25415 25418
• Descriptor: 16S rRNA, 50S ribosomal protein L11, 50S ribosomal protein L13, ... (54 entities in total)
• Functional Keywords: ribosome, hybrid, translocation
• Biological source: Escherichia coli K-12; More
• Total number of polymer chains: 54
• Total formula weight: 2165159.93

Authors

Carbone, C.E.,Korostelev, A.A. (deposition date: 2021-11-11, release date: 2022-02-23)

Primary citation

Carbone, C.E.,Loveland, A.B.,Gamper Jr., H.B.,Hou, Y.M.,Demo, G.,Korostelev, A.A.
Time-resolved cryo-EM visualizes ribosomal translocation with EF-G and GTP.
Nat Commun, 12:7236-7236, 2021

PubMed 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.

PubMed: 34903725
DOI: 10.1038/s41467-021-27415-0

Experimental method

ELECTRON MICROSCOPY (3.2 Å)