2ha3
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Crystal structure of mouse acetylcholinesterase complexed with choline
OverviewOverview
Hydrolysis of acetylcholine catalyzed by acetylcholinesterase (AChE), one, of the most efficient enzymes in nature, occurs at the base of a deep and, narrow active center gorge. At the entrance of the gorge, the peripheral, anionic site provides a binding locus for allosteric ligands, including, substrates. To date, no structural information on substrate entry to the, active center from the peripheral site of AChE or its subsequent egress, has been reported. Complementary crystal structures of mouse AChE and an, inactive mouse AChE mutant with a substituted catalytic serine (S203A), in, various complexes with four substrates (acetylcholine, acetylthiocholine, succinyldicholine, and butyrylthiocholine), two non-hydrolyzable substrate, analogues (m-(N,N,N-trimethylammonio)-trifluoroacetophenone and, 4-ketoamyltrimethylammonium), and one reaction product (choline) were, solved in the 2.05-2.65-A resolution range. These structures, supported by, binding and inhibition data obtained on the same complexes, reveal the, successive positions and orientations of the substrates bound to the, peripheral site and proceeding within the gorge toward the active site, the conformations of the presumed transition state for acylation and the, acyl-enzyme intermediate, and the positions and orientations of the, dissociating and egressing products. Moreover, the structures of the AChE, mutant in complexes with acetylthiocholine and succinyldicholine reveal, additional substrate binding sites on the enzyme surface, distal to the, gorge entry. Hence, we provide a comprehensive set of structural snapshots, of the steps leading to the intermediates of catalysis and the potential, regulation by substrate binding to various allosteric sites at the enzyme, surface.
About this StructureAbout this Structure
2HA3 is a Single protein structure of sequence from Mus musculus with NAG, P6G and CHT as ligands. Active as Acetylcholinesterase, with EC number 3.1.1.7 Full crystallographic information is available from OCA.
ReferenceReference
Substrate and product trafficking through the active center gorge of acetylcholinesterase analyzed by crystallography and equilibrium binding., Bourne Y, Radic Z, Sulzenbacher G, Kim E, Taylor P, Marchot P, J Biol Chem. 2006 Sep 29;281(39):29256-67. Epub 2006 Jul 12. PMID:16837465
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