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Nerve agents (NA) pose as a great risk in the modern world. NA from the V-series, such as VX, are currently recognized as the most toxic among those compounds. However, the emergence of new classes of toxicants recently included in the Chemical Weapons Convention (CWC), such as the A-series NA, a class of organophosphorus compounds related to phosphoramidates, pose a new source of concern due to the lack of information. In order advance in the investigation on the toxicity of such toxic chemicals, we performed in vitro studies to compare representatives of the V- and A-series using affordable surrogates. Results suggest a similar inhibition potency between both agents.
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Acetilcolinesterasa , Agentes Nerviosos , Agentes Nerviosos/toxicidad , Sustancias Peligrosas , Compuestos Organofosforados/toxicidadRESUMEN
The A-series is the most recent generation of chemical warfare nerve agents (CWA) which act directly on the inhibition of the human acetylcholinesterase (HssAChE) enzyme. These compounds lack accurate experimental data on their physicochemical properties, and there is no evidence that traditional antidotes effectively reactivate HssAChE inhibited by them. In the search for potential antidotes, we employed virtual screening, molecular docking, and molecular dynamics (MD) simulations for the theoretical assessment of the performance of a library of Mannich phenols as potential reactivators of HssAChE inhibited by the Novichok agents A-230, A-232, and A-234, in comparison with the commercial oximes pralidoxime (2-PAM), asoxime (HI-6), trimedoxime (TMB-4), and obidoxime. Following the near-attack conformation (NAC) approach, our results suggest that the compounds assessed would face difficulties in triggering the proposed nucleophilic in-line displacement mechanism. Despite this, it was observed that certain Mannich phenols presented similar or superior results to those obtained by reference oximes against A-232 and A-234 model, suggesting that these compounds can adopt more favourable conformations. Additional binding energy calculations confirmed the stability of the model/ligands complexes and the reactivating potential observed in the molecular docking and MD studies. Our findings indicate that the Mannich phenols could be alternative antidotes and that their efficacy should be evaluated experimentally against the A-series CWA.
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Sustancias para la Guerra Química , Reactivadores de la Colinesterasa , Agentes Nerviosos , Humanos , Antídotos/farmacología , Reactivadores de la Colinesterasa/farmacología , Acetilcolinesterasa/metabolismo , Simulación del Acoplamiento Molecular , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/química , Oximas/farmacología , Oximas/química , Trimedoxima/química , Trimedoxima/farmacología , Sustancias para la Guerra Química/farmacología , Compuestos de Piridinio/farmacologíaRESUMEN
Bolivian hemorrhagic fever (BHF) caused by Machupo virus (MACV) is a New World arenavirus having a reported mortality rate of 25-35%. The BHF starts with fever, followed by headache, and nausea which rapidly progresses to severe hemorrhagic phase within 7 days of disease onset. One of the key promoters for MACV viral entry into the cell followed by viral propagation is performed by the viral glycoprotein (GPC). GPC is post-transcriptionally cleaved into GP1, GP2 and a signal peptide. These proteins all take part in the viral infection in host body. Therefore, GPC protein is an ideal target for developing therapeutics against MACV infection. In this study, GPC protein was considered to design a multi-epitope, multivalent vaccine containing antigenic and immunogenic CTL and HTL epitopes. Different structural validations and physicochemical properties were analysed to validate the vaccine. Docking and molecular dynamics simulations were conducted to understand the interactions of the vaccine with various immune receptors. Finally, the vaccine was codon optimised in silico and along with which immune simulation studies was performed in order to evaluate the vaccine's effectiveness in triggering an efficacious immune response against MACV.
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CONTEXT: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the COVID-19 infection and responsible for millions of victims worldwide, remains a significant threat to public health. Even after the development of vaccines, research interest in the emergence of new variants is still prominent. Currently, the focus is on the search for effective and safe drugs, given the limitations and side effects observed for the synthetic drugs administered so far. In this sense, bioactive natural products that are widely used in the pharmaceutical industry due to their effectiveness and low toxicity have emerged as potential options in the search for safe drugs against COVID-19. Following this line, we screened 10 bioactive compounds derived from cholesterol for molecules capable of interacting with the receptor-binding domain (RBD) of the spike protein from SARS-CoV-2 (SC2Spike), responsible for the virus's invasion of human cells. Rounds of docking followed by molecular dynamics simulations and binding energy calculations enabled the selection of three compounds worth being experimentally evaluated against SARS-CoV-2. METHODS: The 3D structures of the cholesterol derivatives were prepared and optimized using the Spartan 08 software with the semi-empirical method PM3. They were then exported to the Molegro Virtual Docking (MVD®) software, where they were docked onto the RBD of a 3D structure of the SC2Spike protein that was imported from the Protein Data Bank (PDB). The best poses obtained from MVD® were subjected to rounds of molecular dynamics simulations using the GROMACS software, with the OPLS/AA force field. Frames from the MD simulation trajectories were used to calculate the ligand's free binding energies using the molecular mechanics - Poisson-Boltzmann surface area (MM-PBSA) method. All results were analyzed using the xmgrace and Visual Molecular Dynamics (VMD) software.
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Productos Biológicos , COVID-19 , Humanos , SARS-CoV-2 , Productos Biológicos/farmacología , Simulación de Dinámica Molecular , Bases de Datos de Proteínas , Simulación del Acoplamiento Molecular , Antivirales/farmacologíaRESUMEN
In the present work, a library of 239 frentizole derivatives formerly synthesized by our research group were virtually screened on the FRB domain of mTOR in a search of potential binders for further experimental evaluation. 39 compounds from this library were virtually selected and classified in 7 groups according to their structural features. 9 representative compounds of these 7 groups were further submitted to rounds of MD simulation and MM-PBSA calculations. Analysis of our results pointed to the most promising among these groups as binders to the FRB domain of mTOR. We believe that they structurally represent a priority portion of the original library for further experimental evaluation.
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Simulación de Dinámica Molecular , Serina-Treonina Quinasas TOR , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Wavelets are mathematical tools used to decompose and represent another function described in the time domain, allowing the study of each component of the original function with a scale-compatible resolution. Thus, these transforms have been used to select conformations from molecular dynamics (MD) trajectories in systems of fundamental and technological interest. Recently, our research group has used wavelets to develop and validate a method, meant to select structures from MD trajectories, which we named OWSCA (optimal wavelet signal compression algorithm). Here, we moved forward on this project by demonstrating the efficacy of this method on the study of three different systems (non-flexible organic, flexible organic, and protein). For each system, 93 wavelets were investigated to verify which is the best one for a given organic system. The results show that the best wavelets were different for each system and, also, very close to the experimental values, with the wavelets db1, rbio 3.1, and bior1.1 being selected for the non-flexible, flexible organic, and protein systems, respectively. This reinforces our OWSCA as a very efficient and promising method for the selection of structures from MD trajectories of different classes of compounds. Our findings also point out that additional studies considering wavelet families are needed for defining the best wavelet for representing each system under study.
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Algoritmos , Simulación de Dinámica Molecular , HumanosRESUMEN
The misuse of novichok agents in assassination attempts has been reported in the international media since 2018. These relatively new class of neurotoxic agents is claimed to be more toxic than the agents of the G and V series and so far, there is no report yet in literature about potential antidotes against them. To shed some light into this issue, we report here the design and synthesis of NTMGMP, a surrogate of A-242 and also the first surrogate of a novichok agent useful for experimental evaluation of antidotes. Furthermore, the efficiency of the current commercial oximes to reactivate NTMGMP-inhibited acetylcholinesterase (AChE) was evaluated. The Ellman test was used to confirm the complete inhibition of AChE, and to compare the subsequent rates of reactivation in vitro as well as to evaluate aging. In parallel, molecular docking, molecular dynamics and MM-PBSA studies were performed on a computational model of the human AChE (HssAChE)/NTMGMP complex to assess the reactivation performances of the commercial oximes in silico. Experimental and theoretical studies matched the exact hierarchy of efficiency and pointed to trimedoxime as the most promising commercial oxime for reactivation of AChE inhibited by A-242.
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Reactivadores de la Colinesterasa , Agentes Nerviosos , Acetilcolinesterasa , Antídotos/farmacología , Inhibidores de la Colinesterasa/toxicidad , Reactivadores de la Colinesterasa/farmacología , Humanos , Simulación del Acoplamiento Molecular , Agentes Nerviosos/toxicidad , Oximas/farmacologíaRESUMEN
Ricin is a potent cytotoxin with no available antidote. Its catalytic subunit, RTA, damages the ribosomal RNA (rRNA) of eukaryotic cells, preventing protein synthesis and eventually leading to cell death. The combination between easiness of obtention and high toxicity turns ricin into a potential weapon for terrorist attacks, urging the need of discovering effective antidotes. On this context, we used computational techniques, in order to identify potential ricin inhibitors among approved drugs. Two libraries were screened by two different docking algorithms, followed by molecular dynamics simulations and MM-PBSA calculations in order to corroborate the docking results. Three drugs were identified as potential ricin inhibitors: deferoxamine, leucovorin and plazomicin. Our calculations showed that these compounds were able to, simultaneously, form hydrogen bonds with residues of the catalytic site and the secondary binding site of RTA, qualifying as potential antidotes against intoxication by ricin.Communicated by Ramaswamy H. Sarma.
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Ricina , Antídotos , Reposicionamiento de Medicamentos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Ricina/química , Ricina/metabolismo , Ricina/farmacologíaRESUMEN
The acute respiratory syndrome caused by the SARS-CoV-2, known as COVID-19, has been ruthlessly tormenting the world population for more than six months. However, so far no effective drug or vaccine against this plague have emerged yet, despite the huge effort in course by researchers and pharmaceutical companies worldwide. Willing to contribute with this fight to defeat COVID-19, we performed a virtual screening study on a library containing Food and Drug Administration (FDA) approved drugs, in a search for molecules capable of hitting three main molecular targets of SARS-CoV-2 currently available in the Protein Data Bank (PDB). Our results were refined with further molecular dynamics (MD) simulations and MM-PBSA calculations and pointed to 7 multi-target hits which we propose here for experimental evaluation and repurposing as potential drugs against COVID-19. Additional rounds of docking, MD simulations and MM-PBSA calculations with remdesivir suggested that this compound can also work as a multi-target drug against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.
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Tratamiento Farmacológico de COVID-19 , SARS-CoV-2 , Proteasas 3C de Coronavirus , Cisteína Endopeptidasas , Humanos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Preparaciones Farmacéuticas , Inhibidores de ProteasasRESUMEN
In this work the DBL3x domain of the erythrocyte membrane protein from Plasmodium Falciparum (PfEMP1), was revisited as a potential molecular target for the development of new drugs against malaria. This protein interacts with chondroitin sulfate A (CSA), a glycosaminoglycan present in the substance fundamental for connective tissues of vertebrates and is implicated in malaria complications in pregnant women. We performed molecular docking and molecular dynamic studies of DBL3x complexed with CSA and five analogues, where the sulfate group was replaced by phosphate, in order to evaluate if the better electrostatic interactions provided by phosphate groups could afford better binders capable of preventing the binding of CSA to DBL3x. Results suggest that all proposed compounds have high affinity towards DBL3x and could bind better to the DBL3x domain of PfEMP1 than CSA, qualifying as potential inhibitors of this protein and, therefore, new potential leads for the drug design against malaria.Communicated by Ramaswamy H. Sarma.
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Malaria Falciparum , Malaria , Complicaciones Parasitarias del Embarazo , Animales , Antígenos de Protozoos/química , Sulfatos de Condroitina/química , Sulfatos de Condroitina/metabolismo , Sulfatos de Condroitina/farmacología , Eritrocitos/metabolismo , Femenino , Glicosaminoglicanos/metabolismo , Humanos , Malaria/complicaciones , Malaria/metabolismo , Malaria Falciparum/tratamiento farmacológico , Proteínas de la Membrana/metabolismo , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Fosfatos , Placenta/metabolismo , Plasmodium falciparum/química , Embarazo , Complicaciones Parasitarias del Embarazo/metabolismo , Proteínas Protozoarias/química , Sulfatos/metabolismoRESUMEN
Continuing the work developed by our research group, in the present manuscript, we performed a theoretical study of 10 new structures derived from the antivirals cidofovir and ribavirin, as inhibitor prototypes for the enzyme thymidylate kinase from Variola virus (VarTMPK). The proposed structures were subjected to docking calculations, molecular dynamics simulations, and free energy calculations, using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method, inside the active sites of VarTMPK and human TMPK (HssTMPK). The docking and molecular dynamic studies pointed to structures 2, 3, 4, 6, and 9 as more selective towards VarTMPK. In addition, the free energy data calculated through the MM-PBSA method, corroborated these results. This suggests that these compounds are potential selective inhibitors of VarTMPK and, thus, can be considered as template molecules to be synthesized and experimentally evaluated against smallpox.
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Organophosphorus poisoning caused by some pesticides and nerve agents is a life-threating condition that must be swiftly addressed to avoid casualties. Despite the availability of medical countermeasures, the clinically available compounds lack a broad spectrum, are not effective towards all organophosphorus toxins, and have poor pharmacokinetics properties to allow them crossing the blood-brain barrier, hampering cholinesterase reactivation at the central nervous system. In this work, we designed and synthesised novel isatin derivatives, linked to a pyridinium 4-oxime moiety by an alkyl chain with improved calculated properties, and tested their reactivation potency against paraoxon- and NEMP-inhibited acetylcholinesterase in comparison to the standard antidote pralidoxime. Our results showed that these compounds displayed comparable in vitro reactivation also pointed by the in silico studies, suggesting that they are promising compounds to tackle organophosphorus poisoning.
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Acetilcolinesterasa/efectos de los fármacos , Reactivadores de la Colinesterasa/farmacología , Isatina/farmacología , Piridinas/farmacología , Simulación por Computador , Técnicas In VitroRESUMEN
BACKGROUND: Neurotoxic chemical warfare agents can be classified as some of the most dangerous chemicals for humanity. The most effective of those agents are the Organophosphates (OPs) capable of restricting the enzyme Acetylcholinesterase (AChE), which in turn, controls the nerve impulse transmission. When AChE is inhibited by OPs, its reactivation can be usually performed through cationic oximes. However, until today, it has not been developed one universal defense agent, with complete effective reactivation activity for AChE inhibited by any of the many types of existing neurotoxic OPs. For this reason, before treating people intoxicated by an OP, it is necessary to determine the neurotoxic compound that was used for contamination, in order to select the most effective oxime. Unfortunately, this task usually requires a relatively long time, raising the possibility of death. Cationic oximes also display a limited capacity of permeating the Blood-Brain Barrier (BBB). This fact compromises their capacity to reactivating AChE inside the nervous system. METHODS: We performed a comprehensive search on the data about OPs available on the scientific literature today in order to cover all the main drawbacks still faced in the research for the development of effective antidotes against those compounds. RESULTS: Therefore, this review about neurotoxic OPs and the reactivation of AChE, provides insights for the new agents' development. The most expected defense agent is a molecule without toxicity and effective to reactivate AChE inhibited by all neurotoxic OPs. CONCLUSION: To develop these new agents, the application of diverse scientific areas of research, especially theoretical procedures as computational science (computer simulation, docking and dynamics), organic synthesis, spectroscopic methodologies, biology, biochemical and biophysical information, medicinal chemistry, pharmacology and toxicology, is necessary.
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Acetilcolinesterasa , Reactivadores de la Colinesterasa , Inhibidores de la Colinesterasa/toxicidad , Reactivadores de la Colinesterasa/farmacología , Simulación por Computador , Humanos , Compuestos Organofosforados/toxicidad , Oximas/farmacologíaRESUMEN
In search of a novel class of compounds against Alzheimer's disease (AD), a new series of 7-chloro-aminoquinoline derivatives containing methylene spacers of different sizes between the 7-chloro-4-aminoquinoline nucleus and imino methyl substituted phenolic rings, and also their reduced analogues, were designed, synthesized and evaluated as neuroprotective agents for AD in vitro. In spite of the multifaceted feature of AD, cholinesterases continue to be powerful and substantial targets, as their inhibition increases both the level and duration of the acetylcholine neurotransmitter action. The compounds presented inhibitory activity in the micromolar range against acetylcholinesterase (AChE) (imines and amines) and butyrylcholineterase (BChE) (amines). The SAR study revealed that elongation of the imine side chain improved AChE activity, whereas the reduction of these compounds to amines was crucial for higher activity and indispensable for BChE inhibition. The most promising selective inhibitors were not cytotoxic and did not stimulate pro-inflammatory activity in glial cells. Kinetic and molecular modeling studies indicated that they also show mixed-type inhibition for both enzymes, behaving as dual-site inhibitors, which can interact with both the peripheral anionic site and the catalytic anionic site of AChE. They could therefore restore cholinergic transmission and also may inhibit the aggregation of Aß promoted by AChE. Additionally, one compound showed promising anti-inflammatory activity by reducing the microglial release of NO⢠at a concentration that is equivalent to the IC50 against BChE (30.32 ± 0.18 µM) and 15-fold greater than the IC50 against AChE (1.97 ± 0.20 µM).Communicated by Ramaswamy H. Sarma.
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Enfermedad de Alzheimer , Fármacos Neuroprotectores , Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/uso terapéutico , Humanos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Relación Estructura-ActividadRESUMEN
Ricin is a toxin found in the castor seeds and listed as a chemical weapon by the Chemical Weapons Convention (CWC) due to its high toxicity combined with the easiness of obtention and lack of available antidotes. The relatively frequent episodes of usage or attempting to use ricin in terrorist attacks reinforce the urge to develop an antidote for this toxin. In this sense, we selected in this work the current RTA (ricin catalytic subunit) inhibitor with the best experimental performance, as a reference molecule for virtual screening in the PubChem database. The selected molecules were then evaluated through docking studies, followed by drug-likeness investigation, molecular dynamics simulations and Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) calculations. In every step, the selection of molecules was mainly based on their ability to occupy both the active and secondary sites of RTA, which are located right next to each other, but are not simultaneously occupied by the current RTA inhibitors. Results show that the three PubChem compounds 18309602, 18498053, and 136023163 presented better overall results than the reference molecule itself, showing up as new hits for the RTA inhibition, and encouraging further experimental evaluation.
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Ricina/antagonistas & inhibidores , Ricina/química , Algoritmos , Sitios de Unión , Sustancias para la Guerra Química/química , Descubrimiento de Drogas , Enlace de Hidrógeno , Ligandos , Conformación Molecular , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Estructura MolecularRESUMEN
This article describes acetylcholinesterase (AChE), an enzyme involved in parasympathetic neurotransmission, its activity, and how its inhibition can be pharmacologically useful for treating dementia, caused by Alzheimer's disease, or as a warfare method due to the action of nerve agents. The chemical concepts related to the irreversible inhibition of AChE, its reactivation, and aging are discussed, along with a relationship to the current international legislation on chemical weapons.
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Acetilcolinesterasa , Envejecimiento/metabolismo , Enfermedad de Alzheimer , Guerra Química/legislación & jurisprudencia , Inhibidores de la Colinesterasa/uso terapéutico , Agentes Nerviosos , Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/enzimología , Proteínas Ligadas a GPI/antagonistas & inhibidores , Proteínas Ligadas a GPI/metabolismo , HumanosRESUMEN
Organophosphorus compounds (OP) are chemicals widely used as pesticides in different applications such as agriculture and public health (vector control), and some of the highly toxic forms have been used as chemical weapons. After application of OPs in an environment, they persist for a period, suffering a degradation process where the biotic factors are considered the most relevant forms. However, to date, the biodegradation of OP compounds is not well understood. There are a plenty of structure-based biodegradation estimation methods, but none of them consider enzymatic interaction in predicting and better comprehending the differences in the fate of OPs in the environment. It is well known that enzymatic processes are the most relevant processes in biodegradation, and that hydrolysis is the main pathway in the natural elimination of OPs in soil samples. Due to this, we carried out theoretical studies in order to investigate the interactions of these OPs with a chosen enzyme-the phosphotriesterase. This one is characteristic of some soils' microorganisms, and has been identified as a key player in many biodegradation processes, thanks to its capability for fast hydrolyzing of different OPs. In parallel, we conducted an experiment using native soil in two conditions, sterilized and not sterilized, spiked with specific amounts of two OPs with similar structure-paraoxon-ethyl (PXN) and O-(4-nitrophenyl) O-ethyl methylphosphonate (NEMP). The amount of OP present in the samples and the appearance of characteristic hydrolysis products were periodically monitored for 40 days using analytical techniques. Moreover, the number of microorganisms present was obtained with plate cell count. Our theoretical results were similar to what was achieved in experimental analysis. Parameters calculated by enzymatic hydrolysis were better for PXN than for NEMP. In soil, PXN suffered a faster hydrolysis than NEMP, and the cell count for PXN was higher than for NEMP, highlighting the higher microbiological toxicity of the latter. All these results pointed out that theoretical study can offer a better comprehension of the possible mechanisms involved in real biodegradation processes, showing potential in exploring how biodegradation of OPs relates with enzymatic interactions.
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Biodegradación Ambiental , Compuestos Organofosforados/química , Plaguicidas/química , Suelo/química , Agricultura , Guerra Química , Humanos , Hidrólisis , Insecticidas/química , Insecticidas/metabolismo , Compuestos Organofosforados/metabolismo , Paraoxon/análogos & derivados , Paraoxon/química , Plaguicidas/toxicidad , Salud Pública , Pirrolidinas/químicaRESUMEN
Casualties caused by organophosphorus pesticides are a burden for health systems in developing and poor countries. Such compounds are potent acetylcholinesterase irreversible inhibitors, and share the toxic profile with nerve agents. Pyridinium oximes are the only clinically available antidotes against poisoning by these substances, but their poor penetration into the blood-brain barrier hampers the efficient enzyme reactivation at the central nervous system. In searching for structural factors that may be explored in future SAR studies, we evaluated neutral aryloximes as reactivators for paraoxon-inhibited Electrophorus eel acetylcholinesterase. Our findings may result into lead compounds, useful for development of more active compounds for emergencies and supportive care.
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Acetilcolinesterasa/metabolismo , Electrophorus/metabolismo , Reactivadores Enzimáticos/farmacología , Oximas/farmacología , Paraoxon/toxicidad , Animales , Reactivadores Enzimáticos/química , Proteínas de Peces/metabolismo , Técnicas In Vitro , Estructura Molecular , Oximas/química , Relación Estructura-ActividadRESUMEN
Studies with oximes have been extensively developed to design new reactivators with better efficiency, and greater spectrum of action. In this study, we aimed to analyze the influence of the Carbamoyl group position change in two isomeric oximes, K203 and K206, on the reactivation percentage of Mus musculus Acetylcholinesterase (MmAChE), inhibited by different nerve agents. Theoretical calculations were performed to assess the difference for the oxime activity with inhibited AChE-complexes and the factors that govern this difference. Comparing theoretical and experimental data, it is possible to observe that this change between the oximes results in different reactivation percentage for the same nerve agent, due to the different interaction modes and activation energy for the studied systems.
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Acetilcolinesterasa/metabolismo , Reactivadores de la Colinesterasa/química , Compuestos Organofosforados/química , Oximas/química , Acetilcolinesterasa/química , Animales , Sitios de Unión , Reactivadores de la Colinesterasa/metabolismo , Diseño de Fármacos , Ratones , Simulación del Acoplamiento Molecular , Agentes Nerviosos/química , Agentes Nerviosos/metabolismo , Compuestos Organofosforados/metabolismo , Compuestos Organotiofosforados/química , Compuestos Organotiofosforados/metabolismo , Teoría Cuántica , TermodinámicaRESUMEN
We report for the first time the efficient use of accelerated solvent extraction (ASE) for extraction of ricin to analytical purposes, followed by the combined use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and MALDI-TOF MS/MS method. That has provided a fast and unambiguous method of ricin identification for in real cases of forensic investigation of suspected samples. Additionally, MALDI-TOF MS was applied to characterize the presence and the toxic activity of ricin in irradiated samples. Samples containing ricin were subjected to ASE, irradiated with different dosages of gamma radiation, and analyzed by MALDI-TOF MS/MS for verification of the intact protein signal. For identification purposes, samples were previously subjected to SDS-PAGE, for purification and separation of the chains, followed by digestion with trypsin, and analysis by MALDI-TOF MS/MS. The results were confirmed by verification of the amino acid sequences of some selected peptides by MALDI-TOF MS/MS. The samples residual toxic activity was evaluated through incubation with a DNA substrate, to simulate the attack by ricin, followed by MALDI-TOF MS/MS analyses.