Structural determinants of selective alpha-conotoxin binding to a nicotinic acetylcholine receptor homolog AChBP.

ABSTRACT: The nicotinic acetylcholine receptor (nAChR) is the prototype member of the superfamily of pentameric ligand-gated ion channels. How the extracellular ligand-binding domain coordinates selective binding of ligand molecules to different subtypes of the receptor is unknown at the structural level. Here, we present the 2.2-A crystal structure of a homolog of the ligand-binding domain of the nAChR, Aplysia californica AChBP (Ac-AChBP), in complex with alpha-conotoxin ImI. This conotoxin is unique in its selectivity toward the neuronal alpha3beta2 and alpha7 nAChR, a feature that is reflected in its selective binding to Ac-AChBP compared with other AChBP homologs. We observe a network of interactions between the residues of the ligand-binding site and the toxin, in which ImI Arg-7 and Trp-10 pl

SUBMITTER: Ulens C 

PROVIDER: S-EPMC1450132 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature