Exploring the effect of surfactants on the interaction between laccase and bisphenol A by molecular docking, molecular dynamics, and energy calculations

Abstract

Bisphenol A (BPA), an endocrine disruptor, has potential threat to human health due to its widespread use as a plasticizer in many industrial products. Laccase (Lac) can degrade BPA well and the intervention of some surfactants can further improve the degradation of BPA by Lac, but the exact details are not known. In this paper, focused on the Lac and BPA, as well as the surfactants rhamnolipid (RL) and polyethylene glycol (PEG) as research objects, we construct nine research systems by molecular docking, and study the effect of these two surfactants on the interaction of Lac-BPA at the molecular level through molecular dynamics (MD) simulation and MM-PBSA prediction. The results showed that these two surfactants aggregated and encapsulated the enzyme in different degrees during the MD simulations, which separated the surface part of the enzyme from the solvent, thereby weakening the environmental influence on Lac activity and changing the local residues conformation of Lac, leading to the reduction of polar solvation free energy and changing the binding state of Lac-BPA. RL promotes the binding of Lac-BPA primarily by influencing the free energy of polar solvents, while PEG weakens the binding free energy of Lac-BPA complex. These results explain the reason for the lower degradation rate of BPA with the addition of PEG than with the addition of RL in the same system under the appropriate conditions. Our work elucidates the mechanism of action by which two surfactants RL and PEG affect the Lac-BPA interaction which will provide a strong basis for improving the degradation of BPA by Lac at the molecular level.