Cryo-EM maps of the E. coli 70S ribosome bound with three aminoacyl-tRNA·EF-Tu·GDP·kir ternary complexes, respectively: yellow: 30S subunit; blue: 50S subunit; purple: A/T-tRNA; red: EF-Tu. (A) Map of the 70S ribosome, at a resolution of ∼10 Å, bearing a Phe-tRNAPhe in the A/T site and a codon UUU in the A site (Valle et al, 2003). (B) Density belonging to the ternary complex (semi-transparent), segmented from the entire ribosome complex shown in (A). Fitting models of tRNA and EF-Tu in ribbon representations. (C) Map of the 70S ribosome, at a resolution of 9 Å, bearing a Trp-tRNATrp in the A/T site and UGG codon in the A site. (D) Map of the ternary complex (semi-transparent), segmented from the ribosome complex shown in (C). Fitting models of EF-Tu (red) and tRNA (pink), both in ribbon representation. (E) The map of the 70S ribosome, at a resolution of 12 Å, bearing a Leu-tRNALeuI in the A/T site and a CUG codon in the A site. (F) Map of the ternary complex (semi-transparent), segmented from the ribosome complex shown in (E). Fitting models of EF-Tu (red) and tRNA (pink), in ribbon representations.