Understanding the bioconjugation reaction of phenthoate with human serum albumin: New insights from experimental and computational approaches.

Organophosphates are chemical pollutants that are existed widely in the environment, but the reactions of these agents with blood proteins are still not fully clarified. The current story was to analyze the static and dynamic interactions between human serum albumin (HSA) and phenthoate and then uncover the impact of the conjugations on the acetylcholinesterase (AChE) activity at the microscopic scale. Experimental results revealed clearly that the bioconjugate of the HSA-phenthoate was yielded and the conformation of HSA can produce autoregulation during the reaction. Dynamic reaction processes suggested that the conformational flexibility of the specific protein domain was changed significantly in equilibrium, and the electrostatic interaction energy played a major role in total energy of the biosystems, which matches the results of wet experiment and molecular docking. We also found that the modes of homologous proteins-phenthoate have obvious distinctions, and this point is related closely to the local dynamic flexibility of biomolecular structures. Additionally, the degree of bioconjugation of the HSA-phenthoate is positively associated with the enzymatic activity of target AChE, which may be attributed to the competitive reactions between HSA and AChE. Evidently, this scenario could provide useful molecular information for the systematic exploration of the toxicokinetics of organophosphorus compounds.