In the present work, we performed a complementary quantum mechanical (QM) study to describe the mechanism by which deprotonated pralidoxime (2-PAM) could reactivate human (Homo sapiens sapiens) acetylcholinesterase (HssAChE) inhibited by the nerve agent VX. Such a reaction is proposed to occur in subsequent addition-elimination steps, starting with a nucleophile bimolecular substitution (SN2) mechanism through the formation of a trigonal bipyramidal transition state (TS). A near attack conformation (NAC), obtained in a former study using molecular mechanics (MM) calculations, was taken as a starting point for this project, where we described the possible formation of the TS. Together, this combined QM/MM study on AChE reactivation shows the feasibility of the reactivation occurring via attack of the deprotonated form of 2-PAM against the Ser203-VX adduct of HssAChE.

• MeSH
• acetylcholinesterasa chemie   účinky léků   MeSH
• katalytická doména MeSH
• kvantová teorie MeSH
• lidé MeSH
• molekulární konformace MeSH
• organothiofosforové sloučeniny farmakologie   MeSH
• pralidoximové sloučeniny chemie   farmakologie   MeSH
• protony MeSH
• serin chemie   MeSH
• simulace molekulární dynamiky MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Organophosphorus compounds have been widely employed to the development of warfare nerve agents and pesticides, resulting in a huge number of people intoxicated annually, being a serious problem of public health. Efforts worldwide have been done in order to design new technologies that are capable of combating or even reversing the poisoning caused by these OP nerve agents. In this line, the bioremediation arises as a promising and efficient alternative for this purpose. As an example of degrading enzymes, there is the organophosphate-degrading (OpdA) enzyme from Agrobacterium radiobacter, which has been quite investigated experimentally due to its high performance in the degradation of neurotoxic nerve agents. This work aims to look into the structural and electronic details that govern the interaction modes of these compounds in the OpdA active site, with the posterior hydrolysis reaction prediction. Our findings have brought about data about the OpdA performance towards different nerve agents, and among them, we may realize that the degradation efficiency strongly depends on the nerve agent structure and its stereochemistry, being in this case the compound Tabun the one more effectively hydrolyzed. By means of the chemical bonds (AIM) and orbitals (FERMO) analysis, it is suggested that the initial reactivity of the OP nerve agents in the OpdA active site does not necessarily dictate the reactivity and interaction modes over the reaction coordinate.

• MeSH
• Agrobacterium tumefaciens enzymologie   MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• biodegradace * MeSH
• biokatalýza MeSH
• fosfatasy chemie   metabolismus   MeSH
• katalytická doména MeSH
• kvantová teorie MeSH
• lidé MeSH
• nervová bojová látka chemie   metabolismus   MeSH
• sarin chemie   metabolismus   MeSH
• simulace molekulového dockingu MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Organophosphorus compounds (OP) nerve agents are among the most toxic chemical substances known. Their toxicity is due to their ability to bind to acetylcholinesterase. Currently, some enzymes, such as phosphotriesterase, human serum paraoxonase 1 and diisopropyl fluorophosphatase, capable of degrading OP, have been characterized. Regarding the importance of bioremediation methods for detoxication of OP, this work aims to study the interaction modes between the human human deoxyuridine triphosphate nucleotidohydrolase (dUTPase) and Sarin and VX, considering their Rp and Sp enantiomers, to evaluate the asymmetric catalysis of those compounds. In previous work, this enzyme has shown good potential to degrade phosphotriesters, and based on this characteristic, we have applied the human dUTPase to the OP degradation. Molecular docking, chemometrics and mixed quantum and molecular mechanics calculations have been employed, showing a good interaction between dUTPase and OP. Two possible reaction mechanisms were tested, and according to our theoretical results, the catalytic degradation of OP by dUTPase can take place via both mechanisms, beyond being stereoselective, that is, dUTPase cleaves one enantiomer preferentially in relation to other. Chemometric techniques provided excellent assistance for performing this theoretical investigation. The dUTPase study shows importance by the fact of it being a human enzyme. Communicated by Ramaswamy H. Sarma.

• MeSH
• analýza hlavních komponent MeSH
• biodegradace MeSH
• katalytická doména MeSH
• kvantová teorie * MeSH
• lidé MeSH
• nervová bojová látka chemie   metabolismus   MeSH
• organofosforové sloučeniny chemie   metabolismus   MeSH
• organothiofosforové sloučeniny chemie   metabolismus   MeSH
• pyrofosfatasy metabolismus   MeSH
• sarin chemie   metabolismus   MeSH
• simulace molekulového dockingu * MeSH
• vodíková vazba MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH