Practice question

Stop codons UAA, UAG, UGA are not recognized by any tRNA but by protein release factors that mimic tRNA shape. In bacteria RF1 decodes UAA and UAG, RF2 decodes UAA and UGA, while in eukaryotes eRF1 recognizes all three. They bind A site when stop codon occupies decoding center, inducing conformational change that positions GGQ motif in peptidyl transferase center to catalyze hydrolysis of P-site peptidyl-tRNA ester bond, freeing protein. Class II factors eRF3 or RF3 GTPases accelerate factor binding and recycling thereafter.