Study of conformational changes in serum albumin by binding of chlorfenvinphos using multispectroscopic techniques and molecular dynamic simulation

Abstract

Chlorfenvinphos has many potential hazards for the environment because of its chemical stability and biological toxicity. Chlorfenvinphos binding properties with serum albumin, SA (human serum albumin, HSA, and bovine serum albumin, BSA) and the protein structural changes have been determined using UV–Vis, fluorescence spectroscopy, molecular docking, and molecular dynamic simulation. The fluorescence emission of HSA/BSA was quenched by chlorfenvinphos. The results revealed that chlorfenvinphos was strongly bound to HSA/BSA [K _b  = (8.08 ± 0.02) × 10⁵ and (2.39 ± 0.04) × 10⁴ dm³ mol⁻¹] and static quenching was confirmed. The distance between the donor (HSA/BSA) and acceptor (chlorfenvinphos), r = 3.73 nm and r = 5.72 nm, was obtained according to fluorescence resonance energy transfer. According to UV–Vis and fluorescence spectroscopy, some changes were observed in conformation of HSA/BSA. Molecular docking studies revealed chlorfenvinphos can bind in the large hydrophobic cavity of subdomain IIA near Trp214 with a binding energy equal to −29.65 kJ mol⁻¹. In addition, BSA can bind near Trp135 with a binding energy equal to −29.57 kJ mol⁻¹. Moreover, MD simulation results suggested that this pesticide could interact with HSA/BSA, probably with a slight modification of its tertiary structure. The results of the different optical techniques and molecular modeling confirmed each other.

Graphical abstract