Didemnin B and ternatin-4 inhibit conformational changes in eEF1A required for aminoacyl-tRNA accommodation into mammalian ribosomes

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-tR...

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Bibliographic Details
Published in:bioRxiv 2022-08
Main Authors: Juette, Manuel F, Carelli, Jordan D, Rundlet, Emily J, Brown, Alan, Shao, Sichen, Ferguson, Angelica, Wasserman, Michael R, Holm, Mikael, Taunton, Jack, Blanchard, Scott C
Format: Article
Language:English
Subjects:
Allosteric properties
Conformation
Electron microscopy
Elongation
mRNA
Natural products
Patent applications
Ribosomes
Transfer RNA
Translation
Translation elongation
tRNA
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Summary: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. Two structurally unrelated cyclic peptides didemnin B and ternatin-4 bind to the eEF1A(GTP)-aa-tRNA ternary complex and inhibit translation. 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 allosteric site on eEF1A, didemnin B and ternatin-4 trap eEF1A in its GTPase-activated conformation, preventing aa-tRNA accommodation on the ribosome. We also show that didemnin B and ternatin-4 exhibit distinct effects on aa-tRNA selection that inform on observed disparities in their inhibition efficacies and physiological impacts. These integrated findings highlight the potential of single-molecule methods to reveal how distinct natural products differentially impact the human translation mechanism. Competing Interest Statement S.C.B. holds an equity interest in Lumidyne Technologies. J.T. is listed as an inventor on a patent application covering ternatin analogs (PCT/US2021/016790, patent pending).
DOI:10.1101/2022.08.01.502281