A catalytic bioscavenger with improved stability and reduced susceptibility to oxidation for treatment of acute poisoning with neurotoxic organophosphorus compounds.

Abstract

Organophosphorus (OP)1 nerve agents pose a severe toxicological threat, both after dissemination in military conflicts and by terrorists. Hydrolytic enzymes, which may be administered into the blood stream of victims by injection and can decompose the circulating nerve agent into non-toxic metabolites in vivo, could offer a treatment. Indeed, for the phosphotriesterase found in the bacterium Brevundimonas diminuta (BdPTE),2 engineered versions with improved catalytic efficiencies have been described; yet, their biochemical stabilities are insufficient for therapeutic use. Here, we describe the application of rational protein design to develop novel mutants of BdPTE that are less susceptible to oxidative damage. In particular, the replacement of two unpaired cysteine residues by more inert amino acids led to higher stability while maintaining high catalytic activity towards a broad spectrum of substrates, including OP pesticides and V-type nerve agents. The mutant BdPTE enzymes were produced in Escherichia coli, purified to homogeneity, and their biochemical and enzymological properties were assessed. Several candidates both revealed enhanced thermal stability and were less susceptible to oxidative stress, as demonstrated by mass spectrometry. These mutants of BdPTE may show promise for the treatment of acute intoxications by nerve agents as well as OP pesticides.

• Authors: Laura Job, Anja Köhler, Benjamin Escher, Franz Worek, Arne Skerra
• Journal: Toxicology letters (Toxicol Lett) Vol. 321 Pg. 138-145 (Mar 15 2020) ISSN: 1879-3169 [Electronic] Netherlands
• PMID: 31891759 (Publication Type: Journal Article)
• Copyright: Copyright © 2019 Elsevier B.V. All rights reserved.

Chemical References

• Antidotes
• Bacterial Proteins
• Nerve Agents
• Organophosphorus Compounds
• Organothiophosphorus Compounds
• Recombinant Proteins
• Soman
• VX
• Sarin
• Phosphoric Triester Hydrolases
• S-(N,N-diethylaminoethyl) isobutyl methylphosphothiolate
• cyclohexyl methylphosphonofluoridate

Topics

• Antidotes (metabolism, pharmacology)
• Bacterial Proteins (genetics, metabolism, pharmacology)
• Caulobacteraceae (enzymology, genetics)
• Drug Stability
• Enzyme Stability
• Hot Temperature
• Mutation
• Nerve Agents (poisoning)
• Organophosphate Poisoning (drug therapy, enzymology)
• Organophosphorus Compounds (toxicity)
• Organothiophosphorus Compounds (poisoning)
• Oxidation-Reduction
• Phosphoric Triester Hydrolases (genetics, metabolism, pharmacology)
• Protein Denaturation
• Recombinant Proteins (pharmacology)
• Sarin (poisoning)
• Soman (poisoning)