Novichok Nerve Agent Research Articles

Novichok Nerve Agents as Inhibitors of Acetylcholinesterase-In Silico Study of Their Non-Covalent Binding Affinity.

In silico studies were performed to assess the binding affinity of selected organophosphorus compounds toward the acetylcholinesterase enzyme (AChE). Quantum mechanical calculations, molecular docking, and molecular dynamics (MD) with molecular mechanics Generalized-Born surface area (MM/GBSA) were applied to assess quantitatively differences between the binding energies of acetylcholine (ACh; the natural agonist of AChE) and neurotoxic, synthetic correlatives (so-called "Novichoks", and selected compounds from the G- and V-series). Several additional quantitative descriptors like root-mean-square fluctuation (RMSF) and the solvent accessible surface area (SASA) were briefly discussed to give-to the best of our knowledge-the first quantitative in silico description of AChE-Novichok non-covalent binding process and thus facilitate the search for an efficient and effective treatment for Novichok intoxication and in a broader sense-intoxication with other warfare nerve agents as well.

Acetohydroxamic acid salts: mild, simple and effective degradation reagents to counter Novichok nerve agents.

Novichoks is the latest known class of organophosphorus nerve agents to be developed. These highly lethal persistent agents, which exert their toxicity mainly through dermal exposure, pose new major challenges in mitigating their effect, mainly in respect to decontamination and medical countermeasures. Herein we report on the effective degradation of Novichok agents (A-230, A-232 and A-234) by hydroxamic acid salts. This class of α-nucleophiles, with emphasis on the FDA approved drug acetohydroxamic acid, were found to promote rapid hydrolysis of these extremely toxic agents. Using 31P NMR the Novichoks degradation rates were determined to be in time scale of minutes with the following order of reactivity A-230>A-232>A-234. The degradation efficiency was found to be dependent on the nucleophiles, their counter-cations and the specific solvent mixture used. Hence, these scavengers can serve as efficient and mild decontaminants in various scenarios including surfaces, dermal decontamination (as an alternative to active lotions such as the RSDL® kit) and also as a medical countermeasure in the form of "catch-up therapy".

Elucidating the degradation mechanism of the nerve agent A-234 using various detergents: a theoretical investigation.

A-234 (ethyl N-[1-(diethylamino)ethylidene]phosphoramidofluoridate) is one of the highly toxic Novichok nerve agents, and its efficient degradation is of significant importance. The possible degradation mechanisms of A-234 by H2O, H2O2, NH3, and their combinations have been extensively investigated by using density functional theory (DFT) calculations. According to the initial intermolecular interaction and the proton transfer patterns between the detergent and the substrate A-234, the A-234 degradation reaction is classified into three categories, denoted as A, B, and C. In modes A and B, the degradation of A-234 by H2O2, H2O, and NH3 is initiated by the nucleophilic attack of the O or N atom of the detergent on the P atom of A-234, coupled with the proton transfer from the detergent to the O or N atom of A-234, whereas in mode C, the direct interaction of H2N-H with the F-P bond of A-234 triggers ammonolysis through a one-step mechanism with the formation of H-F and N-P bonds. Perhydrolysis and hydrolysis of A-234 can be remarkably promoted by introducing the auxiliary NH3, and the timely formed hydrogen bond network among detergent, auxiliary, and substrate molecules is responsible for the enhancement of degradation efficiency.

On-site detection and laboratory verification of the presence of nerve agent biomarkers using dried blood spots

The analysis of biomedical samples is important for the investigation of the alleged exposure to chemical warfare agents. The present study aims to use dried blood spots for portable detection and laboratory verification of organophosphate poisoning. After in-vitro incubation of blood with Novichok A-230, A-232 and A-234 and sarin, a volume of 25 and 50 µL was spotted on a protein saver card. Subsequently, the dried spots were extracted and analyzed by a mobile cholinesterase test kit. In addition, butyrylcholinesterase (BChE) was isolated and digested by pepsin followed by analysis with liquid chromatography tandem mass spectrometry (LC-MS/MS). The fluoride-activated samples were analyzed by gas chromatography tandem mass spectrometry (GC–MS/MS) and LC-MS/MS. It was found that the CWA induced cholinesterase inhibition was remarkably stable in dried blood spots. Even after at least one month storage under ambient conditions, the same linear reduction was visible as function of nerve agent exposure. Additionally, nonapeptide adducts were identified by LC-MS/MS one month after exposure. Also, intact Novichok nerve agents and regenerated sarin were observed by GC–MS/MS. In addition to the stability of the sample, important benefits of the proposed method include the less invasive sample collection and safer and easier shipping and storage conditions. In conclusion, this study shows the feasibility of using on-site detection and state-of-the-art laboratory analysis of dried blood spots for unambiguous verification of nerve agent exposure.

Synthesis, experimental and molecular dynamics simulation of the ESI-CID spectrum of the nerve agent Novichok analog O-2-methoxyethyl N- [bis(dimethylamino)methylidene]-P-methylphosphonamidate

The comprehensive and accurate analysis of mass spectral data is critical for the unequivocal identification of environmental samples containing compounds short-listed by the Chemical Weapons Convention (CWC). In particular, experiments with nerve agents are limited by the high risks involved in their handling. Therefore, the possibility of studying fragmentation pathways by a theoretical approach is especially welcome. In this work, for the first time, O-2-methoxyethyl N- [bis(dimethylamino)methylidene]-P-methylphosphonamidate, an analog of the Novichok nerve agent A-242, was synthesized employing a one-pot microscale synthesis. Electron ionization (EI) and electrospray ionization (ESI) mass spectra (MS) were measured to provide data for CWC verification purposes. Considering that ESI-MS/MS is a powerful method for analyzing non-volatile, highly polar, and very water-soluble compounds, such as degradation products of nerve agents, we extensively investigated for the first time the ESI-(collision-induced dissociation) CID fragmentation pathways of the selected molecule. For this purpose, molecular dynamics simulations using the Quantum Chemical Mass Spectrometry (QCxMS) method employing the semiempirical electronic structure method GFN2-xTB were compared with Triple Quadrupole electrospray ionization (ESI) experimental spectra in positive ion mode. The base peak of the EI spectrum for this molecule was found to be m/z 151, which strongly suggests a McLafferty +1 (ML+1) rearrangement involving the 2-methoxyethyl moiety. The formation of ion the m/z 106 in the ESI-CID spectrum, according to the simulations, results from the rearrangement involving a transfer of one dimethylamino group to the phosphorus atom, a mechanism that would be difficult to identify without employing theoretical methods.

Guarding Against Catastrophic Biological Risks: Preventing State Biological Weapon Development and Use by Shaping Intentions.

Guarding Against Catastrophic Biological Risks: Preventing State Biological Weapon Development and Use by Shaping Intentions.

Characterization of the Interaction of Nerve Agent Mimics with Selected Synthetic Receptors

Qualitative NMR spectroscopic and quantitative calorimetric binding studies were performed to characterize the interaction of nontoxic mimics of the V-type nerve agent VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate) and the Novichok nerve agent A-234 (ethyl (1-(diethylamino)ethylidene)phosphoramidofluoridate) with a series of receptors in 100 mM aqueous phosphate buffer at pH 7.4 and 37 °C. These investigations provided information about the preferred geometry with which the nerve agent mimics are included into the receptor cavities and about the stability of the complexes formed. According to the results, the positively charged VX mimic prefers to bind to cation receptors such as sulfonated calixarenes and an acyclic cucurbituril but does not noticeably interact with cyclodextrins. While binding to the acyclic cucurbituril is stronger than that to calixarenes, the mode of inclusion into the sulfonatocalix[4]arene cavity is better suited for the development of scavengers that bind and detoxify V-type nerve agents. The neutral Novichok mimic, on the other hand, only interacts with the acyclic cucurbituril with a strength required for scavenger development. These binding studies thus provided guidelines for the further development of nerve agent scavengers.

Effective Degradation of Novichok Nerve Agents by the Zirconium Metal-Organic Framework MOF-808.

Novichoks are a novel class of nerve agents (also referred to as the A-series) that were employed in several poisonings over the last few years. This calls for the development of novel countermeasures that can be applied in protective concepts (e.g., protective clothing) or in decontamination methods. The Zr metal-organic framework MOF-808 has recently emerged as a promising catalyst in the hydrolysis of the V- and G-series of nerve agents as well as their simulants. In this paper, we report a detailed study of the degradation of three Novichok agents by MOF-808 in buffers with varying pH. MOF-808 is revealed to be a highly efficient and regenerable catalyst for Novichok agent hydrolysis under basic conditions. In contrast to the V- and G-series of agents, degradation of Novichoks is demonstrated to proceed in two consecutive hydrolysis steps. Initial extremely rapid P-F bond breaking is followed by MOF-catalyzed removal of the amidine group from the intermediate product. The intermediate thus acted as a competitive substrate that was rate-determining for the whole two-step degradation route. Under acidic conditions, the amidine group in Novichok A-230 is more rapidly hydrolyzed than the P-F bond, giving rise to another moderately toxic intermediate. This intermediate could in turn be efficiently hydrolyzed by MOF-808 under basic conditions. These experimental observations were corroborated by density functional theory calculations to shed light on molecular mechanisms.

The CWC at 25: from verification of chemical-weapons destruction to attribution of their use

ABSTRACT This article analyzes the shifting focus of the Chemical Weapons Convention (CWC) during the first 25 years of its implementation, from the verification of destruction of declared chemical-weapon (CW) stockpiles to the attribution of CW use. The article identifies the repeated use of chemical weapons by Syria and the resultant creation of a new attribution norm under the CWC as a critical juncture in the regime’s evolution. Repeated calls for accountability for the use of so-called Novichok nerve agents for assassination purposes serve as the first manifestation of the new attribution norm. The article further outlines steps CWC states parties should take in the context of the Fifth CWC Review Conference in May 2023 to prepare the CW-prohibition regime for its next 25 years of operation by (1) adapting the implementation of key regime norms following the anticipated completion of CW destruction later in 2023 and (2) incorporating the investigation and attribution work of the Investigation and Identification Team into the programmatic work of the OPCW.

A Systematic Review on Nerve Chemical Warfare Agents

Abstract: The recent poisoning of Russian opposition figure and critic Alexei Navalny on August 20th , 2020 with a Soviet-era Novichok nerve agent reminded the world of the use of chemical agents, especially nerve agents to eliminate individual targets or for mass destruction. Nerve agents are a class of organophosphorus compounds. Soman, Sarin, Tabun, Cyclosarin, VX are a few examples of nerve agents. Nerve agents affect a person by disrupting the mechanism by which nerve signals are passed in the body. They inhibit the action of acetylcholinesterase enzyme which is responsible for the breakdown of acetylcholine neurotransmitters leading to accumulation of acetylcholine in the body. Nerve agents have a range of chemical effects on the eye, gastro-intestinal (GI) tract, Central nervous system (CNS), Respiratory system, Cardiovascular system and Neurological system. The management of nerve agent poisoning is done by administering Atropine or Pralidoxime chloride or also by administering anticonvulsants like Benzodiazepines or Diazepam. This review presents all such detailed information on this class of chemical Warfare agents. Keywords: Chemical Warfare Weapon, Nerve Agents, Acetylcholinesterase, Toxicity, Instrumentation

Simulation of the electron ionization mass spectra of the Novichok nerve agent.

Novichok is one of the most feared and controversial nerve agents, which existence was confirmed only after the Salisbury attack in 2018. A new attack on August 2020, in Russia, was confirmed. After the 2018 attack, the agent was included in the list of the most dangerous chemicals of the Chemical Weapons Convention (CWC). However, information related to its electron ionization mass spectrometry (EI/MS), essential for unambiguous identification, is scarce. Therefore, investigations about Novichok EI/MS are urgent. In this work, we employed Born-Oppenheimer molecular dynamics through the Quantum Chemistry Electron Ionization Mass Spectrometry (QCEIMS) method to simulate and rationalize the EI/MS spectra and fragmentation pathways of 32 Novichok molecules recently incorporated into the CWC. The comparison of additional simulations with the measured EI spectrum of another Novichok analog is very favorable. A general scheme of the fragmentation pathways derived from simulation results was presented. The present results will be useful for elucidation and prediction of the EI spectra and fragmentation pathways of the dangerous Novichok nerve agent.

Enzymatic Decontamination of G-Type, V-Type and Novichok Nerve Agents.

Organophosphorus nerve agents (OPNAs) are highly toxic compounds inhibiting cholinergic enzymes in the central and autonomic nervous systems and neuromuscular junctions, causing severe intoxications in humans. Medical countermeasures and efficient decontamination solutions are needed to counteract the toxicity of a wide spectrum of harmful OPNAs including G, V and Novichok agents. Here, we describe the use of engineered OPNA-degrading enzymes for the degradation of various toxic agents including insecticides, a series of OPNA surrogates, as well as real chemical warfare agents (cyclosarin, sarin, soman, tabun, VX, A230, A232, A234). We demonstrate that only two enzymes can degrade most of these molecules at high concentrations (25 mM) in less than 5 min. Using surface assays adapted from NATO AEP-65 guidelines, we further show that enzyme-based solutions can decontaminate 97.6% and 99.4% of 10 g∙m−2 of soman- and VX-contaminated surfaces, respectively. Finally, we demonstrate that these enzymes can degrade ethyl-paraoxon down to sub-inhibitory concentrations of acetylcholinesterase, confirming their efficacy from high to micromolar doses.

Verification of Exposure to Novichok Nerve Agents Utilizing a Semitargeted Human Butyrylcholinesterase Nonapeptide Assay

Novichok (NV) nerve agents were recently added to the list of Schedule 1 chemicals of the Chemical Weapons Convention. There is a well-accepted method for assessment of nerve agent exposure based on mass spectrometric analysis of a nonapeptide with the serine-198 residue modified by the nerve agent, but this approach has not yet been reported for the class of NV agents and requires the availability of reference standards, which may be a limitation for NV agent exposure assessment. Thus, a goal of this study was to first verify the utility of the nonapeptide method for the characterization of human plasma samples exposed in vitro to the NV agents A-230, A-232, and A-234. A second aim was to evaluate the possibility of identifying unknown exposures by applying precursor ion scanning in combination with high resolution mass spectrometry (HRMS). Thus, precursor ion scanning, with a generic fragment ion (m/z 778) of the nonapeptide, was used to pinpoint any modified nonapeptide, while HRMS was used for structural elucidation of the adduct moiety. By this approach, use of HRMS enabled differentiation between adducts of agents with similar molecular masses. A new unique feature that could be exploited for NV nonapeptide analysis was that the modification was released from the peptide during fragmentation in the mass spectrometer and was detected in the low-mass region of the mass spectrum. This low-mass region was extremely informative and contributed to the assignment of the structure of the particular agent used, which is especially important in case no reference materials are available. The presented method is important for verification purposes by the Organisation for Prohibition of Chemical Weapons (OPCW), e.g., in case of investigations of alleged use of NV agents, and for regular forensic investigations.

Organophosphorus poisoning: the wet opioid toxidrome

In The Lancet, David Steindl and colleagues describe the case of a 44-year-old man who was poisoned by a novichok organophosphorus nerve agent. 1 Steindl D Boehmerle W Körner R et al. Novichok nerve agent poisoning. Lancet. 2020; (published online Dec 22.)https://doi.org/10.1016/S0140-6736(20)32644-1 Summary Full Text Full Text PDF Scopus (7) Google Scholar The man was a passenger on a domestic flight in Russia when he became confused, and vomited and collapsed unconscious; 2 h later, he was hospitalised in Omsk, Russia, and treated for respiratory failure and coma. After transfer by air ambulance to Berlin, Germany, features of the cholinergic toxidrome (ie, small or pinpoint pupils, bradycardia, sweating, and hypersalivation) allowed a diagnosis of organophosphorus poisoning to be made. Assessments done by a doctor from the air ambulance crew before transfer to Germany did not indicate that organophosphorus poisoning had yet been diagnosed or antidotes used. However, atropine was later detected in urine. With administration of antidotes and intensive care at Charité-Universitätsmedizin Berlin, the man made a full recovery. Novichok nerve agent poisoningOn Aug 20, 2020, a 44-year-old man who was previously healthy suddenly became confused and began to sweat heavily on a domestic flight in Russia approximately 10 min after departure; he vomited, collapsed, and lost consciousness. After an emergency landing, the man was admitted to the toxicology unit of a local hospital in Omsk, Russia, approximately 2 h after symptom onset. According to the discharge report, the patient presented comatose with hypersalivation and increased diaphoresis and was diagnosed to have respiratory failure, myoclonic status, disturbed carbohydrate metabolism, electrolyte disorders, and metabolic encephalopathy. Full-Text PDF

New Novichok poisoned Navalny

On Oct. 6 the Organisation for the Prohibition of Chemical Weapons released a report confirming that Russian politician Alexei Navalny was poisoned by a Novichok nerve agent. Such agents block messaging from nerves to muscles. The new report confirms the findings of German , French, and Swedish laboratory tests. It says that Navalny’s blood and urine contained the biomarkers of a cholinesterase inhibitor with a similar structure to those of the Novichok chemicals recently added to the Chemical Weapons Convention’s list of chemicals under the most stringent control. However, the nerve agent identified is not included in that list, suggesting that it is a new variant. Navalny first became ill in Russia on Aug. 20 and was airlifted to Berlin a few days later. Now discharged from the hospital, he told German magazine Der Spiegel that his mental abilities have returned and he is undergoing physical therapy.

Novichok compound poisoned Navalny

On Sept. 2, the German government announced that toxicological tests had provided “ ” that Russian opposition leader Alexei Navalny was poisoned with a Novichok nerve agent . “It is therefore clear...

Hydrolysis and enzymatic degradation of Novichok nerve agents

Several parameters of the Novichok nerve agents A230, A232 and A234 were determined. Hydrolysis rates were approximately one to three orders of magnitude slower than G-type nerve agents and approximately zero to two orders of magnitude slower than V-type nerve agents. A230 was the most labile Novichok compound followed by A232 then A234. Activation energies (Ea) and frequency factors (A) were determined for all three compounds. The organophosphorus acid anhydrolase (OPAA) enzyme had catalytic efficiencies on the Novichok compounds ranging between 104 and 105 M−1 min−1 with the highest kcat/Km value for A230, then A232 and lastly, A234.

Evidentiary Thresholds for Unilateral Aggression: Douma, Skripal and Media Analysis of Chemical Weapon Attacks as a Casus Belli

The initiation of military or economic punishment generally on states requires significant justification, lest it be judged an act of aggression. In 2018 two separate incidents invoked similar rationales for such acts of reprisal, specifically that they were responding to attacks using chemical weapons. The incidents were an alleged sarin gas attack by the Syrian government on political opponents, which led to military strikes from the United States, and an alleged poisoning via novichok nerve agents by the Russian government on a Russian ex-spy and his daughter, which led to economic sanctions from the United Kingdom. In both cases, however, evidence of culpability fell short of what legal standards typically require. Despite this, media coverage has failed to examine alternative scenarios or to offer effective critical assessment of the weak rationalizations offered by US and UK governments. The result, precipitate and incautious policy, driven by hasty conclusions rather than careful analysis, represents a failure on the part of both media and government institutions to present the public with an even-handed and neutral assessment of matters vital to their national interest.

Treaty may place tighter control on Novichok nerve agents

Treaty may place tighter control on Novichok nerve agents

Are we facing NOVICHOK nerve agent threat?

Are we facing NOVICHOK nerve agent threat?