Structure of VX-phosphonylated hAChE in complex with oxime reactivator RS194B

Experimental Data Snapshot

  • Resolution: 2.25 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.208 

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Ligand Structure Quality Assessment 

This is version 1.3 of the entry. See complete history


Rational design, synthesis, and evaluation of uncharged, "smart" bis-oxime antidotes of organophosphate-inhibited human acetylcholinesterase.

Gorecki, L.Gerlits, O.Kong, X.Cheng, X.Blumenthal, D.K.Taylor, P.Ballatore, C.Kovalevsky, A.Radic, Z.

(2020) J Biol Chem 295: 4079-4092

  • DOI: https://doi.org/10.1074/jbc.RA119.012400
  • Primary Citation of Related Structures:  
    6U34, 6U37, 6U3P

  • PubMed Abstract: 

    Organophosphate (OP) intoxications from nerve agent and OP pesticide exposures are managed with pyridinium aldoxime-based therapies whose success rates are currently limited. The pyridinium cation hampers uptake of OPs into the central nervous system (CNS). Furthermore, it frequently binds to aromatic residues of OP-inhibited acetylcholinesterase (AChE) in orientations that are nonproductive for AChE reactivation, and the structural diversity of OPs impedes efficient reactivation. Improvements of OP antidotes need to include much better access of AChE reactivators to the CNS and optimized orientation of the antidotes' nucleophile within the AChE active-center gorge. On the basis of X-ray structures of a CNS-penetrating reactivator, monoxime RS194B, reversibly bound to native and venomous agent X (VX)-inhibited human AChE, here we created seven uncharged acetamido bis-oximes as candidate antidotes. Both oxime groups in these bis-oximes were attached to the same central, saturated heterocyclic core. Diverse protonation of the heterocyclic amines and oxime groups of the bis-oximes resulted in equilibration among up to 16 distinct ionization forms, including uncharged forms capable of diffusing into the CNS and multiple zwitterionic forms optimal for reactivation reactions. Conformationally diverse zwitterions that could act as structural antidote variants significantly improved in vitro reactivation of diverse OP-human AChE conjugates. Oxime group reorientation of one of the bis-oximes, forcing it to point into the active center for reactivation, was confirmed by X-ray structural analysis. Our findings provide detailed structure-activity properties of several CNS-directed, uncharged aliphatic bis-oximes holding promise for use as protonation-dependent, conformationally adaptive, "smart" accelerated antidotes against OP toxicity.

  • Organizational Affiliation

    Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0751.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
550Homo sapiensMutation(s): 0 
Gene Names: ACHE
UniProt & NIH Common Fund Data Resources
Find proteins for P22303 (Homo sapiens)
Explore P22303 
Go to UniProtKB:  P22303
PHAROS:  P22303
GTEx:  ENSG00000087085 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP22303
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
PQV (Subject of Investigation/LOI)
Query on PQV

Download Ideal Coordinates CCD File 
D [auth A],
K [auth B]
C10 H19 N3 O2
Query on VX

Download Ideal Coordinates CCD File 
C [auth A],
J [auth B]
C3 H9 O3 P
Query on GOL

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A],
L [auth B],
M [auth B]
C3 H8 O3
Query on NO3

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
I [auth A]
N O3
Experimental Data & Validation

Experimental Data

  • Resolution: 2.25 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.208 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 124.363α = 90
b = 124.363β = 90
c = 129.147γ = 120
Software Package:
Software NamePurpose
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)United StatesU01 NS083451

Revision History  (Full details and data files)

  • Version 1.0: 2020-02-12
    Type: Initial release
  • Version 1.1: 2020-02-19
    Changes: Database references, Derived calculations
  • Version 1.2: 2020-04-08
    Changes: Database references
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Refinement description