Simulations of apo EPAC1 in active and inactive conformations were carried out for 1 µs each, using pmemd.cuda from AMBER22. Trajectories were written out every 10 ps, and simulations were run at 300 K temperature and 1 atm pressure, using Langevin dynamics with γ=2 ps -1 . Features later used for MSM building (section ) were computed using cpptraj v4.25.6 as distributed in AmberTools22.