Figure 2.

Model of the eukaryotic translation termination and recycling pathways. In this model the large ribosomal subunit is drawn as transparent to visualize tRNAs, factors, and mRNA binding to the decoding center at the interface between the large and small subunit. Throughout, GTP is depicted as a green ball and GDP as a red ball; also, the positions of the mRNA, tRNAs, and factors are drawn for clarity and are not meant to specify their exact places on the ribosome. On recognition of a stop codon, the eRF1:eRF3:GTP ternary complex binds to the A site of the ribosome in a preaccommodated state, GTP hydrolysis occurs, and eRF3 is released. ABCE1/Rli1 binds and facilitates the accommodation of eRF1 into an optimally active configuration.