EMD-27691

Single-particle
3.6 Å
EMD-27691 Deposition: 25/07/2022
Map released: 26/10/2022
Last modified: 17/01/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-27691

eEF1A(GDP)aa-tRNA stalled on the human 80S ribosome by didemnin B

EMD-27691

Single-particle
3.6 Å
EMD-27691 Deposition: 25/07/2022
Map released: 26/10/2022
Last modified: 17/01/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Escherichia coli, Homo sapiens, Oryctolagus cuniculus
Sample: eEF1A(GDP)aa-tRNA stalled on the human 80S ribosome by didemnin B

Deposition Authors: Rundlet EJ , Juette MF , Blanchard SC , Ferguson A, Taunton J , Carelli JD
Didemnin B and ternatin-4 differentially inhibit conformational changes in eEF1A required for aminoacyl-tRNA accommodation into mammalian ribosomes.
PUBMED: 36264623
DOI: doi:10.7554/eLife.81608
ISSN: 2050-084X
Abstract:
Rapid and accurate mRNA translation requires efficient codon-dependent delivery of the correct aminoacyl-tRNA (aa-tRNA) to the ribosomal A site. In mammals, this fidelity-determining reaction is facilitated by the GTPase elongation factor-1 alpha (eEF1A), which escorts aa-tRNA as an eEF1A(GTP)-aa-tRNA ternary complex into the ribosome. The structurally unrelated cyclic peptides didemnin B and ternatin-4 bind to the eEF1A(GTP)-aa-tRNA ternary complex and inhibit translation but have different effects on protein synthesis in vitro and in vivo. Here, we employ single-molecule fluorescence imaging and cryogenic electron microscopy to determine how these natural products inhibit translational elongation on mammalian ribosomes. By binding to a common site on eEF1A, didemnin B and ternatin-4 trap eEF1A in an intermediate state of aa-tRNA selection, preventing eEF1A release and aa-tRNA accommodation on the ribosome. We also show that didemnin B and ternatin-4 exhibit distinct effects on the dynamics of aa-tRNA selection that inform on observed disparities in their inhibition efficacies and physiological impacts. These integrated findings underscore the value of dynamics measurements in assessing the mechanism of small-molecule inhibition and highlight potential of single-molecule methods to reveal how distinct natural products differentially impact the human translation mechanism.