Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase. Export

@article{citeulike:769871, 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.}, address = {Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.}, author = {Harel, M. and Schalk, I. and Ehret-Sabatier, L. and Bouet, F. and Goeldner, M. and Hirth, C. and Axelsen, P. H. and Silman, I. and Sussman, J. L.}, citeulike-article-id = {769871}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/8415649}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=8415649}, day = {1}, issn = {0027-8424}, journal = {Proc Natl Acad Sci U S A}, keywords = {1acj, bench\_errors, protein, structure}, month = {October}, number = {19}, pages = {9031--9035}, posted-at = {2006-07-22 19:59:18}, priority = {2}, title = {Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/8415649}, volume = {90}, year = {1993} }

TY - JOUR ID - citeulike:769871 L3 - citeulike-article-id:769871 N2 - 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. IS - 19 JF - Proc Natl Acad Sci U S A SN - 0027-8424 AD - Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel. EP - 9035 TI - Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase. VL - 90 SP - 9031 KW - 1acj KW - bench_errors KW - protein KW - structure AU - Harel, M AU - Schalk, I AU - Ehret-Sabatier, L AU - Bouet, F AU - Goeldner, M AU - Hirth, C AU - Axelsen, PH AU - Silman, I AU - Sussman, JL PY - 1993/10/01/ UR - http://view.ncbi.nlm.nih.gov/pubmed/8415649 ER -