2bys
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CRYSTAL STRUCTURE OF ACHBP FROM APLYSIA CALIFORNICA IN COMPLEX WITH LOBELINE
OverviewOverview
Upon ligand binding at the subunit interfaces, the extracellular domain of, the nicotinic acetylcholine receptor undergoes conformational changes, and, agonist binding allosterically triggers opening of the ion channel. The, soluble acetylcholine-binding protein (AChBP) from snail has been shown to, be a structural and functional surrogate of the ligand-binding domain, (LBD) of the receptor. Yet, individual AChBP species display disparate, affinities for nicotinic ligands. The crystal structure of AChBP from, Aplysia californica in the apo form reveals a more open loop C and, distinctive positions for other surface loops, compared with previous, structures. Analysis of Aplysia AChBP complexes with nicotinic ligands, shows that loop C, which does not significantly change conformation upon, binding of the antagonist, methyllycaconitine, further opens to, accommodate the peptidic antagonist, alpha-conotoxin ImI, but wraps around, the agonists lobeline and epibatidine. The structures also reveal extended, and nonoverlapping interaction surfaces for the two antagonists, outside, the binding loci for agonists. This comprehensive set of structures, reflects a dynamic template for delineating further conformational changes, of the LBD of the nicotinic receptor.
About this StructureAbout this Structure
2BYS is a Single protein structure of sequence from Aplysia californica with as ligand. Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Structures of Aplysia AChBP complexes with nicotinic agonists and antagonists reveal distinctive binding interfaces and conformations., Hansen SB, Sulzenbacher G, Huxford T, Marchot P, Taylor P, Bourne Y, EMBO J. 2005 Oct 19;24(20):3635-46. Epub 2005 Sep 29. PMID:16193063
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