Silman_1999_Chem.Biol.Interact_119-120_43

Reference

Title : A preliminary comparison of structural models for catalytic intermediates of acetylcholinesterase - Silman_1999_Chem.Biol.Interact_119-120_43
Author(s) : Silman I , Millard CB , Ordentlich A , Greenblatt HM , Harel M , Barak D , Shafferman A , Sussman JL
Ref : Chemico-Biological Interactions , 119-120 :43 , 1999
Abstract :

Determination of the three dimensional structure of Torpedo Californica acetylcholinesterase (TcAChE) provided an experimental tool for directly visualizing interaction of AChE with cholinesterase inhibitors of fundamental, pharmacological and toxicological interest. The structure revealed that the active site is located near the bottom of a deep and narrow gorge lined with 14 conserved aromatic amino acids. The structure of a complex of TcAChE with the powerful 'transition state analog' inhibitor, TMTFA, suggested that its orientation in the experimentally determined structure was very similar to that proposed for the natural substrate, acetylcholine, by manual docking. The array of enzyme-ligand interactions visualized in the TMFTA complex also are expected to envelope the unstable TI that forms with acetylcholine during acylation, and to sequester it from solvent. In our most recent studies, the crystal structures of several 'aged' conjugates of TcAChE obtained with OP nerve agents have been solved and compared with that of the native enzyme. The methylphosphonylated-enzyme obtained by reaction with soman provides a useful structural analog for the TI that forms during deacylation after the reaction of TcAChE with acetylcholine. By comparing these structures, we conclude that the same 'oxyanion hole' residues, as well as the aromatic side chains constituting the 'acyl pocket', participate in acylation (TMTFA-AChE) and deacylation (OP-AChE), and that AChE can accommodate both TIs at the bottom of the gorge without major conformational movements.

PubMedSearch : Silman_1999_Chem.Biol.Interact_119-120_43
PubMedID: 10421437
Gene_locus related to this paper: torca-ACHE

Related information

Inhibitor NAF    TMTFA
Gene_locus NAF    TMTFA    torca-ACHE
Structure NAF    TMTFA    torca-ACHE    1AMN

Citations formats

Silman I, Millard CB, Ordentlich A, Greenblatt HM, Harel M, Barak D, Shafferman A, Sussman JL (1999)
A preliminary comparison of structural models for catalytic intermediates of acetylcholinesterase
Chemico-Biological Interactions 119-120 :43

Silman I, Millard CB, Ordentlich A, Greenblatt HM, Harel M, Barak D, Shafferman A, Sussman JL (1999)
Chemico-Biological Interactions 119-120 :43