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.
- MeSH
- acetylcholinesterasa MeSH
- antidota farmakologie MeSH
- cholinesterasové inhibitory toxicita MeSH
- lidé MeSH
- nervová bojová látka * toxicita MeSH
- oximy farmakologie MeSH
- reaktivátory cholinesterázy * farmakologie MeSH
- simulace molekulového dockingu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The nerve agents of the A-series are relatively recent chemical weapons with no antidote available yet. Once inside the human body, those chemicals act similarly to the classic nerve agents, by binding to the catalytic residue Serine 203 (Ser203) of human acetylcholinesterase (HssAChE) and thus preventing the proper function of this enzyme. However, there is no experimental evidence yet if the current antidotes for intoxication by nerve agents are also capable of restoring AChE inhibited by the nerve agents of the A-series. In order to launch some light on this issue, we used computational techniques (molecular docking, molecular dynamics and MM-PBSA interaction energy calculations) to assess the performances of the four currently available commercial oximes (2-PAM, HI-6, obidoxime and trimedoxime) when in contact with HssAChE inhibited by the agent A-242. Based on the near-attack conformation (NAC) criterion, our results suggest that the commercial oximes would have limited efficacy to reactivate the enzyme since they are not able to properly approach the adduct Ser203-A-242. Among those oximes, trimedoxime seems to be the most promising, since it showed lower values of energy in the MM-PBSA calculations, a higher stability inside the catalytic anionic center (CAS) of HssAChE, and was able to adopt a position closer to the NAC that could enable the reactivation mechanism.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- antidota farmakologie MeSH
- cholinesterasové inhibitory chemie toxicita MeSH
- lidé MeSH
- nervová bojová látka * toxicita MeSH
- organofosfáty MeSH
- oximy chemie farmakologie MeSH
- pyridinové sloučeniny farmakologie MeSH
- reaktivátory cholinesterázy * farmakologie MeSH
- simulace molekulového dockingu MeSH
- trimedoxim farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
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.
- MeSH
- antigeny protozoální chemie MeSH
- chondroitin sulfáty chemie metabolismus farmakologie MeSH
- erytrocyty metabolismus MeSH
- fosfáty MeSH
- glykosaminoglykany metabolismus MeSH
- lidé MeSH
- malárie * komplikace metabolismus MeSH
- membránové proteiny metabolismus MeSH
- parazitární komplikace těhotenství * metabolismus MeSH
- placenta metabolismus MeSH
- Plasmodium falciparum chemie MeSH
- protozoální proteiny chemie MeSH
- simulace molekulární dynamiky MeSH
- simulace molekulového dockingu MeSH
- sírany metabolismus MeSH
- těhotenství MeSH
- tropická malárie * farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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.
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.
- MeSH
- biodegradace * MeSH
- chemická válka MeSH
- hydrolýza MeSH
- insekticidy chemie metabolismus MeSH
- lidé MeSH
- organofosforové sloučeniny chemie metabolismus MeSH
- paraoxon analogy a deriváty chemie MeSH
- pesticidy chemie toxicita MeSH
- půda chemie MeSH
- pyrrolidiny chemie MeSH
- veřejné zdravotnictví MeSH
- zemědělství MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The present work aimed to compare the small, neutral and monoaromatic oxime, isatin-3-oxime (isatin-O), to the commercial ones, pralidoxime (2-PAM) and obidoxime, in a search for a new potential reactivator for acetylcholinesterase (AChE) inhibited by the pesticide paraoxon (AChE/POX) as well as a novel potential scaffold for further synthetic modifications. The multicriteria decision methods (MCDM) allowed the identification of the best docking poses of those molecules inside AChE/POX for further molecular dynamic (MD) studies, while Ellman's modified method enabled in vitro inhibition and reactivation assays. In corroboration with the theoretical studies, our experimental results showed that isatin-O have a reactivation potential capable of overcoming 2-PAM at the initial moments of the assay. Despite not achieving better results than obidoxime, this molecule is promising for being an active neutral oxime with capacity of crossing the blood⁻brain barrier (BBB), to reactivate AChE/POX inside the central and peripheral nervous systems. Moreover, the fact that isatin-O can also act as anticonvulsant makes this molecule a possible multipotent reactivator. Besides, the MCDM method showed to be an accurate method for the selection of the best docking poses generated in the docking studies.
- MeSH
- cholinesterasové inhibitory farmakologie MeSH
- erytrocyty účinky léků enzymologie MeSH
- molekulární modely * MeSH
- molekulární struktura MeSH
- oximy chemie farmakologie MeSH
- paraoxon chemie farmakologie MeSH
- reaktivátory cholinesterázy chemie farmakologie MeSH
- simulace molekulární dynamiky MeSH
- simulace molekulového dockingu MeSH
- Publikační typ
- časopisecké články MeSH
In the present work, we performed docking and molecular dynamics simulations studies on two groups of long-tailored oximes designed as peripheral site binders of acetylcholinesterase (AChE) and potential penetrators on the blood brain barrier. Our studies permitted to determine how the tails anchor in the peripheral site of sarin-inhibited human AChE, and which aminoacids are important to their stabilization. Also the energy values obtained in the docking studies corroborated quite well with the experimental results obtained before for these oximes.
- MeSH
- acetylcholinesterasa chemie metabolismus MeSH
- lidé MeSH
- ligandy MeSH
- molekulární konformace MeSH
- oximy chemie farmakologie MeSH
- sarin chemie farmakologie MeSH
- simulace molekulární dynamiky * MeSH
- simulace molekulového dockingu * MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- vodíková vazba MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
