Figure 2. Neomycin-induced effects on intersubunit rotation in wild-type and A1408G aminoglycoside-resistant ribosomes.

(a) (Left) Single-molecule fluorescence (donor—green; acceptor—red) and FRET (blue) trajectories illustrating typical conformational changes in ribosomes labelled as shown in Fig. 1c imaged in the absence of drug. FRET idealization is overlaid in red. (Right) A zoomed-in view highlights the transient nature of the intermediate-FRET state. (b,c) (top panels) smFRET trajectories summed into FRET histograms reveal the population behaviours across a range of neomycin concentrations in (b) wild-type and (c) A1408G ribosomes. (Bottom panels) Initial and final FRET values for each transition summed into two-dimensional histograms (transition density plots). Experiments were performed in triplicate on three separate days.