Perturbation of ribosomal subunit dynamics by inhibitors of tRNA translocation

N state stabilization upon Kan or Par binding to PRE complex. Kan (A) and Par (B) effect on the PRE complex dynamics in the absence of EF-G. Body (teal) and head (pink) FRET fluorescence time courses were monitored in the stopped-flow apparatus upon addition of Kan (30 µM) or Par (5 µM) to PRE complexes. (C) Concentration dependence of k_app values on Kan (0.1–100 µM). k_app values were estimated by single-exponential fitting of time courses as in A. Body (closed symbols) and head (open symbols). Lines show hyperbolic fits. Error bars (which are smaller than symbol site) represent the error of the fit.