1H22

Structure of acetylcholinesterase (E.C. 3.1.1.7) complexed with (S,S)-(-)-bis(10)-hupyridone at 2.15A resolution

Summary for 1H22

• Entry DOI: 10.2210/pdb1h22/pdb
• Related: 1ACJ 1ACL 1AMN 1AX9 1CFJ 1DX6 1E3Q 1E66 1EA5 1EEA 1EVE 1FSS 1GPK 1GPN 1GQR 1GQS 1H23 1HBJ 1JJB 1OCE 1QID 1QIE 1QIF 1QIG 1QIH 1QII 1QIJ 1QIK 1QIM 1QTI 1SOM 1VOT 1VXO 1VXR 2ACE 2ACK 2DFP 3ACE 4ACE
• Descriptor: ACETYLCHOLINESTERASE, (S,S)-(-)-N,N'-DI-5'-[5',6',7',8'-TETRAHYDRO- 2'(1'H)-QUINOLYNYL]-1,10-DIAMINODECANE DIHYDROCHLORIDE, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total)
• Functional Keywords: serine hydrolase, acetylcholinesterase, neurotransmitter cleavage, alzheimer's disease, bivalent ligand, dual-site binding, inhibitor, huperzine a, hydrolase, serine esterase synapse, membrane, nerve, muscle, gpi-anchor neurotransmitter degradation, glycoprotein, bis(10)-hupyrid
• Biological source: TORPEDO CALIFORNICA (PACIFIC ELECTRIC RAY)
• Total number of polymer chains: 1
• Total formula weight: 62234.16

Authors

Wong, D.M.,Greenblatt, H.M.,Carlier, P.R.,Han, Y.-F.,Pang, Y.-P.,Silman, I.,Sussman, J.L. (deposition date: 2002-07-30, release date: 2002-12-23, Last modification date: 2024-11-13)

Primary citation

Wong, D.M.,Greenblatt, H.M.,Dvir, H.,Carlier, P.R.,Han, Y.-F.,Pang, Y.-P.,Silman, I.,Sussman, J.L.
Acetylcholinesterase Complexed with Bivalent Ligands Related to Huperzine A: Experimental Evidence for Species-Dependent Protein-Ligand Complementarity
J.Am.Chem.Soc., 125:363-, 2003

PubMed Abstract: Acetylcholinesterase (AChE) inhibitors improve the cognitive abilities of Alzheimer patients. (-)-Huperzine A [(-)-HupA], an alkaloid isolated from the club moss, Huperzia serrata, is one such inhibitor, but the search for more potent and selective drugs continues. Recently, alkylene-linked dimers of 5-amino-5,6,7,8-tetrahydroquinolinone (hupyridone, 1a), a fragment of HupA, were shown to serve as more potent inhibitors of AChE than (-)-HupA and monomeric 1a. We soaked two such dimers, (S,S)-(-)-bis(10)-hupyridone [(S,S)-(-)-2a] and (S,S)-(-)-bis(12)-hupyridone [(S,S)-(-)-2b] containing, respectively, 10 and 12 methylenes in the spacer, into trigonal TcAChE crystals, and solved the X-ray structures of the resulting complexes using the difference Fourier technique, both to 2.15 A resolution. The structures revealed one HupA-like 1a unit bound to the "anionic" subsite of the active-site, near the bottom of the active-site gorge, adjacent to Trp84, as seen for the TcAChE/(-)-HupA complex, and the second 1a unit near Trp279 in the "peripheral" anionic site at the top of the gorge, both bivalent molecules thus spanning the active-site gorge. The results confirm that the increased affinity of the dimeric HupA analogues for AChE is conferred by binding to the two "anionic" sites of the enzyme. Inhibition data show that (-)-2a binds to TcAChE approximately 6-7- and > 170-fold more tightly than (-)-2b and (-)-HupA, respectively. In contrast, previous data for rat AChE show that (-)-2b binds approximately 3- and approximately 2-fold more tightly than (-)-2a and (-)-HupA, respectively. Structural comparison of TcAChE with rat AChE, as represented by the closely related mouse AChE structure (1maa.pdb), reveals a narrower gorge for rat AChE, a perpendicular alignment of the Tyr337 ring to the gorge axis, and its conformational rigidity, as a result of hydrogen bonding between its hydroxyl group and that of Tyr341, relative to TcAChE Phe330. These structural differences in the active-site gorge explain the switch in inhibitory potency of (-)-2a and 2b and the larger dimer/(-)-HupA potency ratios observed for TcAChE relative to rat AChE. The results offer new insights into factors affecting protein-ligand complementarity within the gorge and should assist the further development of improved AChE inhibitors.

PubMed: 12517147
DOI: 10.1021/JA021111W

Experimental method

X-RAY DIFFRACTION (2.15 Å)