Yeast translation elongation factor eEF3 promotes late stages of tRNA translocation

Ranjan, Namit; Pochopien, Agnieszka A.; Chih-Chien Wu, Colin; Beckert, Bertrand; Blanchet, Sandra; Green, Rachel; Rodnina, Marina and Wilson, Daniel N. (2021): Yeast translation elongation factor eEF3 promotes late stages of tRNA translocation. In: EMBO Journal, Vol. 40, No. 6, e106449

Abstract

In 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 ribosomal 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 slowdown in translation elongation due to accumulation of ribosomes with an occupied A site. Cryo-EM analysis of native 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.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0261-4189
• Language: English