Interactions of mRNA with the E and P sites of the 40S subunit. (A) Fit of the molecular structure of the 80S bound with single tRNA into cryo-EM density. (B) Interactions of mRNA with the elements of the 40S subunit and the anticodon-stem loop of tRNA in the P site (this work). (C) Interactions of mRNA in the 3.1 Å crystal structure of Thermus thermophilus 70S ribosome (PDB ID 3I8G, Jenner et al., 2010). Small-subunit rRNA is in cyan, mRNA in green, P/E-site tRNA in magenta, P-site tRNA in red, ribosomal proteins in marine.