From Proteopediaproteopedia link
ACETYLCHOLINESTERASE (E.C. 22.214.171.124) COMPLEXED WITH HUPERZINE A
[ACES_TORCA] Terminates signal transduction at the neuromuscular junction by rapid hydrolysis of the acetylcholine released into the synaptic cleft. May be involved in cell-cell interactions.
Publication Abstract from PubMed
(-)-Huperzine A (HupA) is found in an extract from a club moss that has been used for centuries in Chinese folk medicine. Its action has been attributed to its ability to strongly inhibit acetylcholinesterase (AChE). The crystal structure of the complex of AChE with optically pure HupA at 2.5 A resolution shows an unexpected orientation for the inhibitor with surprisingly few strong direct interactions with protein residues to explain its high affinity. This structure is compared to the native structure of AChE devoid of any inhibitor as determined to the same resolution. An analysis of the affinities of structural analogues of HupA, correlated with their interactions with the protein, shows the importance of individual hydrophobic interactions between HupA and aromatic residues in the active-site gorge of AChE.
Structure of acetylcholinesterase complexed with the nootropic alkaloid, (-)-huperzine A.,Raves ML, Harel M, Pang YP, Silman I, Kozikowski AP, Sussman JL Nat Struct Biol. 1997 Jan;4(1):57-63. PMID:8989325
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.