mAChE-anti TZ2PA5 complex

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.215 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.191 

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Ligand Structure Quality Assessment 

This is version 2.1 of the entry. See complete history


Steric and Dynamic Parameters Influencing In Situ Cycloadditions to Form Triazole Inhibitors with Crystalline Acetylcholinesterase.

Bourne, Y.Sharpless, K.B.Taylor, P.Marchot, P.

(2016) J Am Chem Soc 138: 1611-1621

  • DOI: https://doi.org/10.1021/jacs.5b11384
  • Primary Citation of Related Structures:  
    5EHN, 5EHQ, 5EHZ, 5EIA, 5EIE, 5EIH

  • PubMed Abstract: 

    Ligand binding sites on acetylcholinesterase (AChE) comprise an active center, at the base of a deep and narrow gorge lined by aromatic residues, and a peripheral site at the gorge entry. These features launched AChE as a reaction vessel for in situ click-chemistry synthesis of high-affinity TZ2PA6 and TZ2PA5 inhibitors, forming a syn-triazole upon cycloaddition within the gorge from alkyne and azide reactants bound at the two sites, respectively. Subsequent crystallographic analyses of AChE complexes with the TZ2PA6 regioisomers demonstrated that syn product association is accompanied by side chain reorganization within the gorge, freezing-in-frame a conformation distinct from an unbound state or anti complex. To correlate inhibitor dimensions with reactivity and explore whether in situ cycloaddition could be accelerated in a concentrated, crystalline template, we developed crystal-soaking procedures and solved structures of AChE complexes with the TZ2PA5 regioisomers and their TZ2/PA5 precursors (2.1-2.7 Å resolution). The structures reveal motions of residue His447 in the active site and, unprecedentedly, residue Tyr341 at the gorge mouth, associated with TZ2 binding and coordinated with other side chain motions in the gorge that may guide AChE toward a transient state favoring syn-triazole formation. Despite precursor binding to crystalline AChE, coupling of rapid electric field fluctuations in the gorge with proper alignments of the azide and alkyne reactants to form the triazole remains a likely limiting step. These observations point to a prime requirement for AChE to interconvert dynamically between sequential conformations to promote favorable electrostatic factors enabling a productive apposition of the reactants for reactivity.

  • Organizational Affiliation

    Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
543Mus musculusMutation(s): 0 
Gene Names: Ache
UniProt & NIH Common Fund Data Resources
Find proteins for P21836 (Mus musculus)
Explore P21836 
Go to UniProtKB:  P21836
IMPC:  MGI:87876
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP21836
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
Glycosylation Resources
GlyTouCan:  G21290RB
GlyCosmos:  G21290RB
GlyGen:  G21290RB
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
5O2 Binding MOAD:  5EHQ Ki: 0.03 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.215 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.191 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.82α = 90
b = 113.16β = 90
c = 225.92γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata 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: 2016-01-20
    Type: Initial release
  • Version 1.1: 2016-02-17
    Changes: 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: 2024-01-10
    Changes: Data collection, Database references, Derived calculations, Refinement description, Structure summary