All of these receptor channels are probably hetero- or homopentameric. The best characterized are the nicotinic acetyl-choline receptors which are pentameric channels of a 2 bgd subunit composition.
All subunits are homologous.
The three dimensional structures of the protein complex in both the open and closed configurations have been solved at 0.9 nm resolution. These structural features are probably general for all members of the family. Opening of ligand-gated ion channels. Acetylcholine receptor channel imaged in the open state. Structural biology of key nervous system proteins.