GSE160206 eEF3 promotes late stages of tRNA translocation on the ribosome

Contributors : Colin Wu ; Rachel GreenSeries Type : OtherOrganism : Saccharomyces cerevisiaeIn 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 analys is 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, enabl ing presentation of a revised yeast translation elongation cycle.

Source: GEO: Gene Expression Omnibus - October 28, 2020 Category: Genetics & Stem Cells Tags: Other Saccharomyces cerevisiae Source Type: research