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-Structure paper
Title | Didemnin B and ternatin-4 differentially inhibit conformational changes in eEF1A required for aminoacyl-tRNA accommodation into mammalian ribosomes. |
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Journal, issue, pages | Elife, Vol. 11, Year 2022 |
Publish date | Oct 20, 2022 |
Authors | Manuel F Juette / Jordan D Carelli / Emily J Rundlet / Alan Brown / Sichen Shao / Angelica Ferguson / Michael R Wasserman / Mikael Holm / Jack Taunton / Scott C Blanchard / |
PubMed 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 ...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. |
External links | Elife / PubMed:36264623 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.2 - 4.1 Å |
Structure data | EMDB-27691: eEF1A(GDP)aa-tRNA stalled on the human 80S ribosome by didemnin B EMDB-27694: eEF1A(GDP)aa-tRNA stalled on the human 80S ribosome by ternatin-4 EMDB-27732: eEF1A(GDP)aa-tRNA stalled on the rabbit 80S ribosome by ternatin-4 |
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