Electrostatic potential surface maps. Electrostatic potential surface maps were for the representative trajectory from most occupied cluster grouping. (A) GPRV in the active conformation, (B) GPRPAAC, (C) GPRPFPAC, (D) GPRVVAAC, (E) GPRPPERC, (F) GPRPPERC rotated 180° about the vertical axis, (G) GPRVVERC, and (H) GPRVVERC rotated 180° about the vertical axis.