PMID: 19326912
Paz A, Xie Q, Greenblatt HM, Fu W, Tang Y, Silman I, Qiu Z, Sussman JL
The Crystal Structure of a Complex of Acetylcholinesterase with a Bis-(-)-nor-meptazinol Derivative Reveals Disruption of the Catalytic Triad.
J Med Chem. 2009 Mar 27.
A bis-(-)-nor-meptazinol derivative in which the two meptazinol rings are linked by a nonamethylene spacer is a novel acetylcholinesterase inhibitor that inhibits both catalytic activity and Abeta peptide aggregation. The crystal structure of its complex with Torpedo californica acetylcholinesterase was determined to 2.7 A resolution. The ligand spans the active-site gorge, with one nor-meptazinol moiety bound at the "anionic" subsite of the active site, disrupting the catalytic triad by forming a hydrogen bond with His440N(epsilon2), which is hydrogen-bonded to Ser200O(gamma) in the native enzyme. The second nor-meptazinol binds at the peripheral "anionic" site at the gorge entrance. A number of GOLD models of the complex, using both native TcAChE and the protein template from the crystal structure of the bis-(-)-nor-meptazinol/TcAChE complex, bear higher similarity to the X-ray structure than a previous model obtained using the mouse enzyme structure. These findings may facilitate rational design of new meptazinol-based acetylcholinesterase inhibitors.