Eukaryotic cytoplasmic ribosome 60S subunit, E site (60S E-site)

The Eukaryotic cytoplasmic ribosome 60S subunit, E site (exit site) is a critical functional region within the large ribosomal subunit responsible for the release of deacylated tRNA during protein synthesis (Garreau de Loubresse et al., 2014). During the elongation phase of translation, the ribosome moves along the mRNA, and the tRNA that has donated its amino acid to the growing polypeptide chain shifts from the P-site to the E-site before being ejected (Budkevich et al., 2011). This site is composed of both ribosomal RNA (rRNA) and ribosomal proteins, providing a specific structural pocket that coordinates with the tRNA's CCA-end. While the E-site is essential for maintaining the reading frame and ensuring efficient translocation, it also serves as a target for various small-molecule inhibitors. For example, glutarimide antibiotics like cycloheximide bind specifically to the 60S E-site, blocking the translocation of tRNA and effectively halting protein synthesis (Schneider-Poetsch et al., 2010). Although many E-site inhibitors are too toxic for systemic human use due to their impact on host translation, they are invaluable tools in molecular biology and serve as templates for developing selective antifungal agents.

Other names

Large ribosomal subunit exit site60S exit siteRibosomal E-siteEukaryotic 60S E-site

Inhibitors bind to the E-site of the 60S subunit, sterically hindering the translocation of deacylated tRNA from the P-site to the E-site or preventing its release, thereby arresting the elongation phase of protein translation.