Torpedo californica acetylcholinesterase in complex with a chlorotacrine-tryptophan hybrid inhibitor

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 

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Ligand Structure Quality Assessment 

This is version 2.2 of the entry. See complete history


Novel tacrine-tryptophan hybrids: Multi-target directed ligands as potential treatment for Alzheimer's disease.

Chalupova, K.Korabecny, J.Bartolini, M.Monti, B.Lamba, D.Caliandro, R.Pesaresi, A.Brazzolotto, X.Gastellier, A.J.Nachon, F.Pejchal, J.Jarosova, M.Hepnarova, V.Jun, D.Hrabinova, M.Dolezal, R.Zdarova Karasova, J.Mzik, M.Kristofikova, Z.Misik, J.Muckova, L.Jost, P.Soukup, O.Benkova, M.Setnicka, V.Habartova, L.Chvojkova, M.Kleteckova, L.Vales, K.Mezeiova, E.Uliassi, E.Valis, M.Nepovimova, E.Bolognesi, M.L.Kuca, K.

(2019) Eur J Med Chem 168: 491-514

  • DOI: https://doi.org/10.1016/j.ejmech.2019.02.021
  • Primary Citation of Related Structures:  
    5NUU, 6I0B, 6I0C

  • PubMed Abstract: 

    A combination of tacrine and tryptophan led to the development of a new family of heterodimers as multi-target agents with potential to treat Alzheimer's disease. Based on the in vitro biological profile, compound S-K1035 was found to be the most potent inhibitor of human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE), demonstrating balanced IC 50 values of 6.3 and 9.1 nM, respectively. For all the tacrine-tryptophan heterodimers, favorable inhibitory effect on hAChE as well as on hBChE was coined to the optimal spacer length ranging from five to eight carbon atoms between these two pharmacophores. S-K1035 also showed good ability to inhibit Aβ 42 self-aggregation (58.6 ± 5.1% at 50 μM) as well as hAChE-induced Aβ 40 aggregation (48.3 ± 6.3% at 100 μM). The X-ray crystallographic analysis of TcAChE in complex with S-K1035 pinpointed the utility of the hybridization strategy applied and the structures determined with the two K1035 enantiomers in complex with hBChE could explain the higher inhibition potency of S-K1035. Other in vitro evaluations predicted the ability of S-K1035 to cross blood-brain barrier and to exert a moderate inhibition potency against neuronal nitric oxide synthase. Based on the initial promising biochemical data and a safer in vivo toxicity compared to tacrine, S-K1035 was administered to scopolamine-treated rats being able to dose-dependently revert amnesia.

  • Organizational Affiliation

    National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic; Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Acetylcholinesterase543Tetronarce californicaMutation(s): 0 
Find proteins for P04058 (Tetronarce californica)
Explore P04058 
Go to UniProtKB:  P04058
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04058
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G86851RC
GlyCosmos:  G86851RC
GlyGen:  G86851RC
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
C, D
Glycosylation Resources
GlyTouCan:  G81315DD
GlyCosmos:  G81315DD
GlyGen:  G81315DD
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 9A5

Download Ideal Coordinates CCD File 
E [auth A](2~{S})-2-azanyl-~{N}-[6-[(6-chloranyl-1,2,3,4-tetrahydroacridin-9-yl)amino]hexyl]-3-(1~{H}-indol-3-yl)propanamide
C30 H36 Cl N5 O
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 111.87α = 90
b = 111.87β = 90
c = 137.591γ = 120
Software Package:
Software NamePurpose
iMOSFLMdata reduction
Aimlessdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-05-30
    Type: Initial release
  • Version 1.1: 2019-08-14
    Changes: Data collection, Database references
  • Version 1.2: 2019-08-21
    Changes: Data collection, Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2021-05-12
    Changes: Derived calculations, Structure summary
  • Version 2.2: 2024-01-17
    Changes: Data collection, Database references, Refinement description