Schematic description of the free energy landscape near the equilibrium state at two levels of resolution. (A) CG description, where a single (global) energy minimum is observed. The surface is color-coded from green (lowest energy) to red (highest). In the normal mode description, the energy profile is a quadratic function along each mode axis. Mode 1 axis refers to the direction of motion (away from the minimum) that requires the least ascent in energy for a given displacement. (B) A higher resolution. Two substates, A and B, are distinguished, with lower energy than that observed in the CG model. Substate A is more stable (has lower free energy) than B. Mode 1 directions coincide in both representations.