Sampling simulations without and with DEN restraints. All-atom RMSD are computed with respect to the target (closed) conformation of RBP for sampling simulations starting from the open conformation and using electron density maps computed at seven different resolutions (dmin = 3, 4, 6, 8, 10, 15, and 20 Å). (A) Free sampling simulation without DEN. (B) Sampling simulations using the DEN restraints with γ = 0.8. With the DEN restraints, all simulations yielded structures with RMSDs below 1.5 Å (indicated by the grey shaded region).