2bys: Difference between revisions

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.

2BYS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aplysia_californica Aplysia californica] with LOB as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BYS OCA].  

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