Harel_1993_Proc.Natl.Acad.Sci.U.S.A_90_9031

Reference

Title : Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase - Harel_1993_Proc.Natl.Acad.Sci.U.S.A_90_9031
Author(s) : Harel M , Schalk I , Ehret-Sabatier L , Bouet F , Goeldner M , Hirth C , Axelsen PH , Silman I , Sussman JL
Ref : Proceedings of the National Academy of Sciences of the United States of America , 90 :9031 , 1993
Abstract :

Binding sites of Torpedo acetylcholinesterase (EC 3.1.1.7) for quaternary ligands were investigated by x-ray crystallography and photoaffinity labeling. Crystal structures of complexes with ligands were determined at 2.8-A resolution. In a complex with edrophonium, and quaternary nitrogen of the ligand interacts with the indole of Trp-84, and its m-hydroxyl displays bifurcated hydrogen bonding to two members of the catalytic triad, Ser-200 and His-440. In a complex with tacrine, the acridine is stacked against the indole of Trp-84. The bisquaternary ligand decamethonium is oriented along the narrow gorge leading to the active site; one quaternary group is apposed to the indole of Trp-84 and the other to that of Trp-279, near the top of the gorge. The only major conformational difference between the three complexes is in the orientation of the phenyl ring of Phe-330. In the decamethonium complex it lies parallel to the surface of the gorge; in the other two complexes it is positioned to make contact with the bound ligand. This close interaction was confirmed by photoaffinity labelling by the photosensitive probe 3H-labeled p-(N,N-dimethylamino)benzenediazonium fluoroborate, which labeled, predominantly, Phe-330 within the active site. Labeling of Trp-279 was also observed. One mole of label is incorporated per mole of AcChoEase inactivated, indicating that labeling of Trp-279 and that of Phe-330 are mutually exclusive. The structural and chemical data, together, show the important role of aromatic groups as binding sites for quaternary ligands, and they provide complementary evidence assigning Trp-84 and Phe-330 to the "anionic" subsite of the active site and Trp-279 to the "peripheral" anionic site.

PubMedSearch : Harel_1993_Proc.Natl.Acad.Sci.U.S.A_90_9031
PubMedID: 8415649
Gene_locus related to this paper: torca-ACHE

Related information

Inhibitor Decamethonium    Edrophonium    Tacrine
Gene_locus Decamethonium    Edrophonium    Tacrine    torca-ACHE
Structure Decamethonium    Edrophonium    Tacrine    torca-ACHE    1ACJ    1ACL    2ACK

Citations formats

Harel M, Schalk I, Ehret-Sabatier L, Bouet F, Goeldner M, Hirth C, Axelsen PH, Silman I, Sussman JL (1993)
Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase
Proceedings of the National Academy of Sciences of the United States of America 90 :9031

Harel M, Schalk I, Ehret-Sabatier L, Bouet F, Goeldner M, Hirth C, Axelsen PH, Silman I, Sussman JL (1993)
Proceedings of the National Academy of Sciences of the United States of America 90 :9031