Quantitation of M2/M3 loop movements during the MD simulations showing greatly enhanced dynamics in th e apo state. (A–C) C_α RMSD for each protomer from the individual simulations (md0-md2) after alignment of the TMD relative to the starting structure (PDB accession no. 5VRF). (D) C_α RMSD distributions for loop motion relative to the TMD, representing all the simulations as calculated by KDE. (E–G) C_α RMSD for each protomer after alignment of the loop relative to the starting structure. (H) C_α RMSD distributions for the intrinsic loop motion, representing all the simulations in the apo and holo states (repeated from Fig. 5 B to aid comparison).