Extended Data Fig. 3: Ligand coordination in the “agonist pockets” under the loops C at various inter-subunit interfaces.

All pockets in which a ligand was observed in our structures are shown with a single representative example. Potential hydrogen bonds are displayed as dashed yellow lines. Histamine and GABA in the β3⁺/α4⁻ pocket are taken from the α4β3δ + GABA + histamine structure. THIP in the β3⁺/α4⁻ and δ⁺/β3⁻ pocket is taken from the α4β3δ + THIP + histamine structure. Histamine in the β3⁺/β3⁻ pocket is taken from the α4β3δ + histamine structure. HEPES in the β3⁺/β3⁻ pocket is taken from the "apo" α4β3δ structure. GABA in the β3⁺/γ2⁻ pocket is taken from the α4β3γ2 + GABA structure. Chain IDs represented in the panels are given as capital letters next to the subunit type.