(A–D) Toe-printing analysis of ribosomal complexes obtained by treating pre-TCs formed on Stem-MVHL-STOP mRNA with combinations of eRF1, eRF3, puromycin, ABCE1, Met-tRNAiMet and eIFs 2/3/1/1A/3j/4A/4B/4F/4G at the indicated free [Mg2+]. The positions of pre- and post-TCs are indicated by black arrows; positions of 48S complexes formed at the AUG triplets upstream and downstream of the stop codon are shown in red and blue, respectively. (E-G) Dissociation of pre-TCs, assembled on Stem-MVHL-STOP mRNA with [32P]60S subunits after incubation with combinations of eRFs, ABCE1 and eIFs at the indicated [Mg2+], assayed by SDG centrifugation. Upper fractions were omitted for clarity.