Fig. 2

Inferred mRNA–tRNA base-pair free-energy differences on the ribosome during frameshifting. a Probability densities (colored histograms) of the free-energy differences ΔG_bp for the P-site base pairs obtained from the model based on the full FS data set (64 FS values, blue), and a set of the FS values measured in vivo by Tsuchihashi et al.²⁶ (21 FS values, green). b Probability densities for changing A-site base pairs. c Probability densities for changing P-site and A-site base pairs simultaneously. d FS from experiment compared to that calculated from the free-energy model. Each panel shows FS values for a tRNA pair (rmsd 2.5%). e For cross-validation of the model, iteratively, each FS value was predicted using free-energy differences obtained from all other FS values (rmsd 4.1%). For each mRNA sequence, one square is centered at the mean value and the width and height correspond to two times the standard deviation