Figure 3.

Relaxation kinetics of water mapped on A_2A AR structure. (A) Location of the microswitches. (B) Time correlation functions of water from six key residues are fitted to multiexponential functions (see the Supporting Material). (C) Average relaxation time of water from various regions (TM, ECL, and ICL) in the apo (black), agonist-bound (red), and antagonist-bound (blue) forms. The extracellular view of the TM helices is shown on the left. TM1, TM2, and TM7, which have much longer relaxation time in the agonist-bound form, are marked in red. (D–F) Water relaxation time (τ) from each residue in (D) the apo, (E) the agonist-bound, and (F) the antagonist-bound forms. The TM regions are shaded in gray, and the positions of microswitches are marked with cyan dots. The receptor structures are colored based on the τ-values. To see this figure in color, go online.