Fig. 8. Comparison of the tRNA (A) and eRF1 (B) crystallographic structures. The similarity of the structures is shown by a side view (left) and a front view (right). Regions displaying similar roles (anticodon versus KS and CCA versus GGQ) are colored yellow. Molecular structures are shown by their water accessible surfaces, and the N domain is dark blue. (C) Enlarged view of the N domain of eRF1 showing the relative positions of the site of crosslink (yellow) and of residues E55, S123 and Y125 (orange), previously proposed to contact the base moiety of the invariant U residue of stop codons (Bertram et al., 2000; Muramatsu et al., 2001, Inagaki et al., 2002). Pink sticks show amino acids connecting the N and M domains.