Exploring the mode of binding between butylated hydroxyanisole with bovine serum albumin: Multispectroscopic and molecular docking study

•A 1:1 complex was formed between BHA and BSA through hydrophobic interaction.•BHA induced conformational changes of BSA.•The presence of food additives decreased the binding affinity of BHA with BSA. Considering the harm of BHA on humans, thorough research of the effect of BHA on the structure of serum albumin is necessary. The binding mechanisms of BHA with bovine serum albumin (BSA) and the effects of other three food additives (butylated hydroxytoluene, benzoic acid and citric acid) on BHA-BSA system were researched by multispectroscopy and molecular docking. The fluorescence quenching experiment results showed that the fluorescence quenching mechanism of BSA by BHA was static quenching. The binding constant ((5.70 ± 0.38) × 103 M−1 at 298 K) and thermodynamic parameters (ΔH = 110.8 ± 2.91 kJ·mol−1 and ΔS = 443.3 ± 9.30 J·mol−1·K−1) indicated that BHA and BSA formed a relatively stable complex through hydrophobic interaction. Three-dimensional fluorescence spectra confirmed the conformation changes of BSA due to the binding of BHA. Site marker competitive experiments and molecular docking proved that BHA could bind BSA into site I in subdomain IIA. The results of molecular docking showed that BHA formed hydrophobic interactions with amino acid residues (Ala290, Leu237, Leu259, Ile263 and Ile289). The presence of other food additives weakened the binding of BHA to BSA.