P-site pairing subtleties revealed by the effects of different tRNAs on programmed translational bypassing where anticodon re-pairing to mRNA is separated from dissociation.

Programmed ribosomal bypassing occurs in decoding phage T4 gene 60 mRNA. Half the ribosomes bypass a 50 nucleotide gap between codons 46 and 47. Peptidyl-tRNA dissociates from the "take-off" GGA, codon 46, and re-pairs to mRNA at a matched GGA "landing site" codon directly 5' of codon 47 where translation resumes.