Discovery, Biological Evaluation, and Crystal Structure of a Novel Nanomolar Selective Butyrylcholinesterase Inhibitor

Abstract

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 β(1-42) peptide self-induced aggregation into fibrils (by 61.7% at 10 μM) and protected cultured SH-SY5Y cells against amyloid-β-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.

Scaffold Hopping and Bioisosteric Replacements Based on Binding Site Alignments

“…To demonstrate the usefulness of our approach, we applied it to a previously published nanomolar butyrylcholinesterase inhibitor [20] (PDB code: 3F9) serving as a reference compound (Figure 4, upper half). First, the inhibitor structure was fragmented, enabling recognition of its basic structural elements.…”

Insights into (S)-rivastigmine inhibition of butyrylcholinesterase (BuChE): Molecular docking and saturation transfer difference NMR (STD-NMR)

“…The X-ray crystal structure of hBuChE has already been solved, as well as an X-ray crystal structure of a hBuChE-piperidinecontaining amide complex, besides this inhibitor gave an IC 50 of 21.3 nM and a dissociation constant of 2.7 nM [23]. hBuChE is characterized by possessing the catalytic triad which is constituted by S198, E325 and H438, the hydrophobic residues L286 and V288, which define the acyl pocket, these changes make the binding with the bulkier butyrate substrate possible [23].…”

“…hBuChE is characterized by possessing the catalytic triad which is constituted by S198, E325 and H438, the hydrophobic residues L286 and V288, which define the acyl pocket, these changes make the binding with the bulkier butyrate substrate possible [23]. Residues F288 and F290 in AChE are replaced by L286 and V288 in BuChE [23].…”

“…By contrast there is less information available on the molecular nature of the BuChE-rivastigmine interactions. Human BuChE (hBuChE) and human AChE (hAChE) share 65% amino acid sequence homology [17].…”

Synthesis, characterization andin vitroevaluation of substitutedN-(2-phenylcyclopropyl)carbamates as acetyl- and butyrylcholinesterase inhibitors

“…11 24 . Moreover, selective BChE inhibitors do not exhibit the adverse cholinergic effects, which are characteristic for AChE inhibitors [25][26][27][28] . Therefore, the research concerned in the selective BChE inhibitors is currently a promising direction in medicinal chemistry research.…”