Exploration of the intermolecular isoproturon–bovine serum albumin combination: Biophysical and computational prospects

Binding orientations of IPU in BSA binding site II. [Display omitted] •Molecular interaction of isoproturon–bovine serum albumin is first investigated.•IPU quenched the BSA fluorescence through the static process.•The IPU–BSA complex was stabilize with a weak binding strength.•Hydrophobic interactions, van der Waals interactions and H-bonds associated in the interaction process.•Site II of BSA is the chosen locus for IPU binding. Isoproturon (IPU), a selective systemic herbicide that is frequently applied to eradicate large-leaved weeds and annual grasses in agricultural fields. However, the accumulation of IPU residues during food production might negatively affect on human and animal health. To comprehend the impact of IPU on the mankind and environment, the interaction analysis of IPU with plasma protein is crucial. This work used a variety of techniques, including fluorescence, UV–vis absorption, computational docking and dynamics simulation to extensively examine the combination of IPU with bovine serum albumin (BSA) under typical physiological settings. IPU quenched the BSA fluorescence and form the IPU–BSA complex through a static process. A weak binding affinity was anticipated (binding constant = 4.68–2.48 × 103 M−1) for IPU–BSA interaction. Thermodynamic results revealed that the IPU–BSA binding reaction was a spontaneous process, predominantly governed by hydrogen bonds, van der Waals and hydrophobic forces, which was well supported by molecular docking analysis. Synchronous and three-dimensional fluorescence spectral results exhibited microenvironmental fluctuations near the protein’s Trp and Tyr residues with added IPU, but inclusion of IPU to BSA was observed to enhance the protein’s thermal constancy. Site marker displacement results demonstrated that IPU desirably binds to BSA at site II. An in silico findings also unveiled the primary binding arrangement of IPU was placed at site II of BSA and surrounded by hydrophobic and polar residues. Molecular dynamics simulation results suggested the IPU–BSA complex persisted compact and stable.