Inventory of states in a pre-translocational sample of rabbit liver ribosomes. From left to right: states are termed classical-1, classical-2, rotated-1 and rotated-2. A-, P- and E-site tRNA are painted pink, green, and orange, respectively. Yellow = 40S subunit, blue = 60S subunit. The PRE-translocation complex bearing deacylated tRNAPhe in the P site and N-acetyl-Lys-tRNA Lys3 in the A site was prepared by stepwise addition of purified tRNAs to reassociated 80S ribosomes (0.8 μM) programmed with MFK-mRNA. (Reproduced from [32]; with permission by Cell Press).