The many paths to frameshifting: kinetic modelling and analysis of the effects of different elongation steps on programmed –1 ribosomal frameshifting

Liao, Pei-Yu; Choi, Yong Seok; Dinman, Jonathan D.; Lee, Kelvin H.

As PRF occurs during translation elongation, models of À1 PRF should be described within this context. The elongation cycle can be divided into four stages. First, the ribosome selects the cognate aminoacyl-tRNA (aa-tRNA) according to the codon at the decoding center (decoding, DC in Figure 1 ). Second, the aa-tRNA moves from A/T entry state into the A/A state to be accommodated into the ribosome (aa-tRNA accommodation, AA in Figure 1 ). Third, the ribosome catalyses peptidyltransfer, resulting in a peptidyl tRNA in the A-site and a deacylated tRNA in the P site (peptidyltransfer, PT in Figure 1 ). Fourth, the peptidyl-tRNA moves from the A-site to the P-site, carrying the mRNA along, and the deacylated tRNA moves out of the P-site into the E-site from where it dissociates (translocation, TL in Figure 1 ). Translocation opens up the ribosomal A-site and the ribosome moves on to another round of aa-tRNA selection.