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bioRxiv · 10.1101/2020.07.01.182105

eEF3 promotes late stages of tRNA translocation on the ribosome

Ranjan, N.·Pochopien, A. A.·Wu, C. C.-C.·Beckert, B.·Blanchet, S.·Green, R.·Rodnina, M. V.·Wilson, D. N.
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Abstract

SummaryIn addition to the conserved translation elongation factors eEF1A and eEF2, fungi require a third essential elongation factor, eEF3. While eEF3 has been implicated in tRNA binding and release at the A and E sites, its exact mechanism of action is unclear. Here we show that eEF3 acts at the mRNA–tRNA translocation step by promoting the dissociation of the tRNA from the E site, but independent of aminoacyl-tRNA recruitment to the A site. Depletion of eEF3 in vivo leads to a general slow-down in translation elongation due to accumulation of ribosomes with an occupied A site. Cryo-EM analysis of ex vivo eEF3-ribosome complexes shows that eEF3 facilitates late steps of translocation by favoring non-rotated ribosomal states as well as by opening the L1 stalk to release the E-site tRNA. Additionally, our analysis provides structural insights into novel translation elongation states, enabling presentation of a revised yeast translation elongation cycle.Competing Interest StatementThe authors have declared no competing interest.View Full Text

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Ranjan, N., Pochopien, A. A., Wu, C. C.-C., Beckert, B., Blanchet, S., Green, R., Rodnina, M. V., Wilson, D. N.. 2020-07-01. eEF3 promotes late stages of tRNA translocation on the ribosome. https://doi.org/10.1101/2020.07.01.182105

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