We also found that the equilibrium length of the distance restraint has an impact on the mobility of the ligands, meaning that the chosen restraint force constant should vary with the distance restraint length chosen (if a constant level of ligand motion is the goal). In particular, the arc length s the ligand can move along around the surface of a sphere, where s = rθ and r is the distance and θ the angle P1-L1-L2, scales roughly quadratically with the distance. Therefore, we increase the force constant of that angle restraint quadratically with the distance.