Figure 5.

2D PMF underlying the motion of the αC-helix and the A-loop in c-Src. The unit of this PMF is in kcal/mol. d₁ is the distance between E310 Cδ atom and R409 Cζ atom. d₂ is the distance between E310 Cδ atom and K295 Nζ atom. d₃ is the average of the following three distances and is used to reflect the opening of the A-loop in the process. Those three distances are between O(Asp413) and N(Thr417), O(Asn414) and N(Ala418), and O(Glu415) and N(Arg419). The free energy basin that is located at the lower left corner is the inactive conformation, while that at the top right corner corresponds to the active conformation.