Fig. 2.

Twelve homology models of the M₂ receptor superposed on the 3UON crystal structure. Homology models (color) of the M₂ receptor based on the templates listed in Table 1 are superposed using MUSTANG [27] implemented in YASARA on the crystal structure 3UON (gray). Orientation: extracellular site up, TM VI and TM VII front. Colors: purple—α-helix; yellow—β-sheet; cyan—turn; white—coil. RMSDs of the models to the target structure (3UON) are listed in Table 4