Butyrylcholinesterase (BChE) is regarded as a promising drug target as its levels and activity significantly increase in the late stages of Alzheimer's disease. To discover novel BChE inhibitors, we used a hierarchical virtual screening protocol followed by biochemical evaluation of 40 highest scoring hit compounds. Three of the compounds identified showed significant inhibitory activities against BChE. The most potent, compound 1 (IC50 = 21.3 nM), was resynthesized and resolved into its pure enantiomers. A high degree of stereoselective activity was revealed, and a dissociation constant of 2.7 nM was determined for the most potent stereoisomer (+)-1. The crystal structure of human BChE in complex with compound (+)-1 was solved, revealing the binding mode and providing clues for potential optimization. Additionally, compound 1 inhibited amyloid beta1-42 peptide self-induced aggregation into fibrils (by 61.7% at 10 muM) and protected cultured SH-SY5Y cells against amyloid-beta-induced toxicity. These data suggest that compound 1 represents a promising candidate for hit-to-lead follow-up in the drug-discovery process against Alzheimer's disease.
Representative scheme of BCHE structure and an image from PDBsum server
Databases
PDB-Sum
4TPK Previously Class, Architecture, Topology and Homologous superfamily - PDB-Sum server
FSSP
4TPKFold classification based on Structure-Structure alignment of Proteins - FSSP server
