3DKK

Aged Form of Human Butyrylcholinesterase Inhibited by Tabun


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.197 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Aging of Cholinesterases Phosphylated by Tabun Proceeds through O-Dealkylation.

Carletti, E.Li, H.Li, B.Ekstrom, F.Nicolet, Y.Loiodice, M.Gillon, E.Froment, M.T.Lockridge, O.Schopfer, L.M.Masson, P.Nachon, F.

(2008) J.Am.Chem.Soc. 130: 16011-16020

  • DOI: 10.1021/ja804941z
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Human butyrylcholinesterase (hBChE) hydrolyzes or scavenges a wide range of toxic esters, including heroin, cocaine, carbamate pesticides, organophosphorus pesticides, and nerve agents. Organophosphates (OPs) exert their acute toxicity through inhibi ...

    Human butyrylcholinesterase (hBChE) hydrolyzes or scavenges a wide range of toxic esters, including heroin, cocaine, carbamate pesticides, organophosphorus pesticides, and nerve agents. Organophosphates (OPs) exert their acute toxicity through inhibition of acetylcholinesterase (AChE) by phosphorylation of the catalytic serine. Phosphylated cholinesterase (ChE) can undergo a spontaneous, time-dependent process called "aging", during which the OP-ChE conjugate is dealkylated. This leads to irreversible inhibition of the enzyme. The inhibition of ChEs by tabun and the subsequent aging reaction are of particular interest, because tabun-ChE conjugates display an extraordinary resistance toward most current oxime reactivators. We investigated the structural basis of oxime resistance for phosphoramidated ChE conjugates by determining the crystal structures of the non-aged and aged forms of hBChE inhibited by tabun, and by updating the refinement of non-aged and aged tabun-inhibited mouse AChE (mAChE). Structures for non-aged and aged tabun-hBChE were refined to 2.3 and 2.1 A, respectively. The refined structures of aged ChE conjugates clearly show that the aging reaction proceeds through O-dealkylation of the P(R) enantiomer of tabun. After dealkylation, the negatively charged oxygen forms a strong salt bridge with protonated His438N epsilon2 that prevents reactivation. Mass spectrometric analysis of the aged tabun-inhibited hBChE showed that both the dimethylamine and ethoxy side chains were missing from the phosphorus. Loss of the ethoxy is consistent with the crystallography results. Loss of the dimethylamine is consistent with acid-catalyzed deamidation during the preparation of the aged adduct for mass spectrometry. The reported 3D data will help in the design of new oximes capable of reactivating tabun-ChE conjugates.


    Organizational Affiliation

    Département de Toxicologie, Centre de Recherches du Service de Santé des Armées, 38700 La Tronche, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cholinesterase
A
529Homo sapiensMutation(s): 4 
Gene Names: BCHE (CHE1)
EC: 3.1.1.8
Find proteins for P06276 (Homo sapiens)
Go to Gene View: BCHE
Go to UniProtKB:  P06276
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CL
Query on CL

Download SDF File 
Download CCD File 
A
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
FUL
Query on FUL

Download SDF File 
Download CCD File 
A
BETA-L-FUCOSE
6-DEOXY-BETA-L-GALACTOSE
C6 H12 O5
SHZGCJCMOBCMKK-KGJVWPDLSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
SEN
Query on SEN
A
L-peptide linkingC5 H13 N2 O5 PSER
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.197 
  • Space Group: I 4 2 2
Unit Cell:
Length (Å)Angle (°)
a = 155.240α = 90.00
b = 155.240β = 90.00
c = 127.470γ = 90.00
Software Package:
Software NamePurpose
PROCDdata collection
XDSdata reduction
REFMACrefinement
XSCALEdata scaling
PDB_EXTRACTdata extraction
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-12-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Non-polymer description, Version format compliance