Interactions of three bisphenol analogues with hemoglobin investigated by spectroscopy and molecular docking

Bisphenol F (BPF), bisphenol S (BPS), and bisphenol B (BPB) have been extensively used in food packaging, plasticizer, and paper products, causing more concern about their biosafety. The mechanism of these bisphenols' toxicity was investigated by determining diverse effects of them on common protein bovine hemoglobin (BHb). The effects at the molecular level were determined by ultraviolet-visible, circular dichroism, resonance light scattering, fluorescence spectroscopy, and molecular docking. The irreversible cross-linking results of bisphenols and BHb demonstrate that hydrogen (H) bonding and hydrophobic forces play major roles in the interaction. Both BPF and BPS decreased the amount of α-helix, leading to the loosening of protein skeleton while BPB made little change. In the loose structure, BPF exposed the internal amino acids to a hydrophobic environment and BPS (above 10μM) obviously quenched characteristic fluorescence. The variant effects of BPF, BPS, and BPB may arise from different structural formula. Accordingly, BPB could be used as a better substitute for bisphenol A, and it is necessary to control the concentration of BPS and BPF below 10μM in application. This study provided important basis for application of BPB and safe use of bisphenol analogues in industry.