Figure 1.

The best theoretical binding position of (s)-nicotine and (s)-6-hydroxynicotine at the α9-α9 interface of α9 nAChRs (A,B), α3-β2 (C,D) and α5-α3 (E,F) interfaces of α3β2α5 nAChRs (2:2:1 stoichiometry) and α3-β4 (G,H) and α5-α3 (I,J) interfaces of α3β4α5 nAChRs (2:2:1 stoichiometry). The ligands are displayed as balls and sticks, the NIC-binding residues are shown as sticks (the residues with side chains colored in blue and marked with “+” belong to the principal side while the residues with side chains colored in green and marked with “–” belong to the complementary side). The hydrogen bonds are shown as green dashed lines and the rest of the receptor as molecular surface.