2BYQ

Crystal structure of Aplysia californica AChBP in complex with epibatidine

Summary for 2BYQ

• Entry DOI: 10.2210/pdb2byq/pdb
• Related: 2BR7 2BR8 2BYN 2BYP 2BYR 2BYS
• Descriptor: SOLUBLE ACETYLCHOLINE RECEPTOR, EPIBATIDINE (2 entities in total)
• Functional Keywords: receptor, acetylcholine binding protein, nicotinic acetylcholine, conformational flexibility, agonist
• Biological source: APLYSIA CALIFORNICA (CALIFORNIA SEA HARE)
• Total number of polymer chains: 5
• Total formula weight: 130307.15

Authors

Hansen, S.B.,Sulzenbacher, G.,Huxford, T.,Marchot, P.,Taylor, P.,Bourne, Y. (deposition date: 2005-08-03, release date: 2005-10-05, Last modification date: 2024-11-06)

Primary citation

Hansen, S.B.,Sulzenbacher, G.,Huxford, T.,Marchot, P.,Taylor, P.,Bourne, Y.
Structures of Aplysia Achbp Complexes with Nicotinic Agonists and Antagonists Reveal Distinctive Binding Interfaces and Conformations.
Embo J., 24:3635-, 2005

PubMed Abstract: 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.

PubMed: 16193063
DOI: 10.1038/SJ.EMBOJ.7600828

Experimental method

X-RAY DIFFRACTION (3.4 Å)