Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation

Eugénie Carletti, He Li, Bin Li, Fredrik Ekström, Yvain Nicolet, Mélanie Loiodice, Emilie Gillon, Marie T. Froment, Oksana Lockridge, Lawrence M Schopfer, Patrick Masson, Florian Nachon

Research output: Contribution to journalArticle

80 Citations (Scopus)

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 inhibition of acetylcholinesterase (AChE) by phosphylation 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 Å, 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 His438Nε2 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.

Original languageEnglish (US)
Pages (from-to)16011-16020
Number of pages10
JournalJournal of the American Chemical Society
Volume130
Issue number47
DOIs
StatePublished - Nov 26 2008

Fingerprint

Dealkylation
Cholinesterases
Enzyme inhibition
Aging of materials
Pesticides
Butyrylcholinesterase
Oximes
Crystallography
Enantiomers
Mass spectrometry
Toxicity
Organophosphates
Phosphorus
Esters
Acetylcholinesterase
Enzymes
Crystal structure
Salts
Oxygen
Acids

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Carletti, E., Li, H., Li, B., Ekström, F., Nicolet, Y., Loiodice, M., ... Nachon, F. (2008). Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation. Journal of the American Chemical Society, 130(47), 16011-16020. https://doi.org/10.1021/ja804941z

Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation. / Carletti, Eugénie; Li, He; Li, Bin; Ekström, Fredrik; Nicolet, Yvain; Loiodice, Mélanie; Gillon, Emilie; Froment, Marie T.; Lockridge, Oksana; Schopfer, Lawrence M; Masson, Patrick; Nachon, Florian.

In: Journal of the American Chemical Society, Vol. 130, No. 47, 26.11.2008, p. 16011-16020.

Research output: Contribution to journalArticle

Carletti, E, Li, H, Li, B, Ekström, F, Nicolet, Y, Loiodice, M, Gillon, E, Froment, MT, Lockridge, O, Schopfer, LM, Masson, P & Nachon, F 2008, 'Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation', Journal of the American Chemical Society, vol. 130, no. 47, pp. 16011-16020. https://doi.org/10.1021/ja804941z
Carletti E, Li H, Li B, Ekström F, Nicolet Y, Loiodice M et al. Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation. Journal of the American Chemical Society. 2008 Nov 26;130(47):16011-16020. https://doi.org/10.1021/ja804941z
Carletti, Eugénie ; Li, He ; Li, Bin ; Ekström, Fredrik ; Nicolet, Yvain ; Loiodice, Mélanie ; Gillon, Emilie ; Froment, Marie T. ; Lockridge, Oksana ; Schopfer, Lawrence M ; Masson, Patrick ; Nachon, Florian. / Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation. In: Journal of the American Chemical Society. 2008 ; Vol. 130, No. 47. pp. 16011-16020.
@article{2ef222403d814d4fa800a8944ba0b3c2,
title = "Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation",
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 inhibition of acetylcholinesterase (AChE) by phosphylation 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 {\AA}, 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 His438Nε2 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.",
author = "Eug{\'e}nie Carletti and He Li and Bin Li and Fredrik Ekstr{\"o}m and Yvain Nicolet and M{\'e}lanie Loiodice and Emilie Gillon and Froment, {Marie T.} and Oksana Lockridge and Schopfer, {Lawrence M} and Patrick Masson and Florian Nachon",
year = "2008",
month = "11",
day = "26",
doi = "10.1021/ja804941z",
language = "English (US)",
volume = "130",
pages = "16011--16020",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "47",

}

TY - JOUR

T1 - Aging of cholinesterases phosphylated by tabun proceeds through O-dealkylation

AU - Carletti, Eugénie

AU - Li, He

AU - Li, Bin

AU - Ekström, Fredrik

AU - Nicolet, Yvain

AU - Loiodice, Mélanie

AU - Gillon, Emilie

AU - Froment, Marie T.

AU - Lockridge, Oksana

AU - Schopfer, Lawrence M

AU - Masson, Patrick

AU - Nachon, Florian

PY - 2008/11/26

Y1 - 2008/11/26

N2 - 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 phosphylation 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 Å, 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 His438Nε2 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.

AB - 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 phosphylation 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 Å, 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 His438Nε2 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.

UR - http://www.scopus.com/inward/record.url?scp=56749185596&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=56749185596&partnerID=8YFLogxK

U2 - 10.1021/ja804941z

DO - 10.1021/ja804941z

M3 - Article

VL - 130

SP - 16011

EP - 16020

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 47

ER -