Fig. 4. Free energy landscapes and structures of the GTP-bound Q61A KRAS: (A) showing free energy landscape constructed by using RMSD of backbone atoms and the distance of Y32 away from E63 as reaction coordinates, in which E1, E2, E3 and E4 indicate energy valleys detected by MR-GaMD simulations, (B), (C), (D) and (E) corresponding to representative structures located at energy valleys E1, E2, E3 and E4, respectively, and (F) displaying superimpositions of GTP, residue Y32 and ions in four representative structures with that in the crystal structure (6MNX). The unit of the distances is Å and that of free energy is kcal mol⁻¹.