1ACL

QUATERNARY LIGAND BINDING TO AROMATIC RESIDUES IN THE ACTIVE-SITE GORGE OF ACETYLCHOLINESTERASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 

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Literature

Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase.

Harel, M.Schalk, I.Ehret-Sabatier, L.Bouet, F.Goeldner, M.Hirth, C.Axelsen, P.H.Silman, I.Sussman, J.L.

(1993) Proc Natl Acad Sci U S A 90: 9031-9035

  • DOI: https://doi.org/10.1073/pnas.90.19.9031
  • Primary Citation of Related Structures:  
    1ACJ, 1ACL

  • PubMed Abstract: 

    Binding sites of Torpedo acetylcholinesterase (EC 3.1.1.7) for quaternary ligands were investigated by x-ray crystallography and photoaffinity labeling. Crystal structures of complexes with ligands were determined at 2.8-A resolution. In a complex with edrophonium, and quaternary nitrogen of the ligand interacts with the indole of Trp-84, and its m-hydroxyl displays bifurcated hydrogen bonding to two members of the catalytic triad, Ser-200 and His-440. In a complex with tacrine, the acridine is stacked against the indole of Trp-84. The bisquaternary ligand decamethonium is oriented along the narrow gorge leading to the active site; one quaternary group is apposed to the indole of Trp-84 and the other to that of Trp-279, near the top of the gorge. The only major conformational difference between the three complexes is in the orientation of the phenyl ring of Phe-330. In the decamethonium complex it lies parallel to the surface of the gorge; in the other two complexes it is positioned to make contact with the bound ligand. This close interaction was confirmed by photoaffinity labelling by the photosensitive probe 3H-labeled p-(N,N-dimethylamino)benzenediazonium fluoroborate, which labeled, predominantly, Phe-330 within the active site. Labeling of Trp-279 was also observed. One mole of label is incorporated per mole of AcChoEase inactivated, indicating that labeling of Trp-279 and that of Phe-330 are mutually exclusive. The structural and chemical data, together, show the important role of aromatic groups as binding sites for quaternary ligands, and they provide complementary evidence assigning Trp-84 and Phe-330 to the "anionic" subsite of the active site and Trp-279 to the "peripheral" anionic site.


  • Organizational Affiliation

    Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ACETYLCHOLINESTERASE537Tetronarce californicaMutation(s): 0 
EC: 3.1.1.7
UniProt
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
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
DME
Query on DME

Download Ideal Coordinates CCD File 
B [auth A]DECAMETHONIUM ION
C16 H38 N2
MTCUAOILFDZKCO-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 113.05α = 90
b = 113.05β = 90
c = 137.5γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-08-31
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2016-06-29
    Changes: Derived calculations
  • Version 1.4: 2024-01-17
    Changes: Data collection, Database references, Derived calculations, Other