The published structures for the 70S ribosome from E. coli [PDB accession numbers: 2AVY, 2AW4; (2)], as well as yeast 80S structures from yeast (1S1I, 1S1H, 3JYV, 3JYW, 3JYX; (4, 12) ] were used in the analysis of this work and the generation of figures. Published T. thermophilus 70S subunits containing A-site, P-site and E-site Phe-tRNA were also employed (1G1X, (5) . All structures were visualized and manipulated using MacPyMol software (30) .