Water-Regulated Mechanisms for Degradation of Pesticides Paraoxon and Parathion by Phosphotriesterase: Insight from QM/MM and MD Simulations.
Chem Asian J
; 17(14): e202200439, 2022 Jul 15.
Article
em En
| MEDLINE
| ID: mdl-35586954
ABSTRACT
The enzymatic degradation of pesticides paraoxon (PON) and parathion (PIN) by phosphotriesterase (PTE) has been investigated by QM/MM calculations and MD simulations. In the PTE-PON complex, Znα and Znß in the active site are five- and six-coordinated, respectively, while both zinc ions are six coordinated with the Znα -bound water molecule (WT1) for the PTE-PIN system. The hydrolytic reactions for PON and PIN are respectively driven by the nucleophilic attack of the bridging-OH- and the Znα -bound water molecule on the phosphorus center of substrate, and the two-step hydrolytic process is predicted to be the rate-limiting step with the energy spans of 13.8 and 14.4â
kcal/mol for PON and PIN, respectively. The computational studies reveal that the presence of the Znα -bound water molecule depends on the structural feature of substrates characterized by P=O and P=S, which determines the hydrolytic mechanism and efficiency for the degradation of organophosphorus pesticides by PTE.
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MEDLINE
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Hidrolases de Triester Fosfórico
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En
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Chem Asian J
Ano de publicação:
2022
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Article