Binding interaction studies of sodium benzoate, calcium propionate and sodium propionate with bovine serum albumin using spectroscopic method and molecular docking

The study investigated the in vitro interaction of bovine serum albumin (BSA) with sodium benzoate (SB), calcium propionate (CP) and sodium propionate (SP) and their consequent health impact on foods and pharmaceuticals when utilized as additives. The binding interaction studies of the compounds were investigated under simulated physiological conditions using spectroscopic analysis and molecular docking with thermodynamic parameters obtained to determine the nature of binding forces. The UV spectra for the three analytes revealed significant hypochromic effect of BSA-ligand interactions compared to only BSA indicating a modification of the BSA conformation due to possible hydrophobic interactions between the aromatic rings of the amino acids and ligands and other non-covalent interactions. Thermodynamic parameters obtained shows the binding interactions are exothermic, spontaneous, and hydrogen bonding and van der Waal’s forces are chiefly responsible for formation and stabilization of BSA binding with SB, CP and SP and with additional pi-alkyl interactions observed for SB binding. Docking studies depict that hydrogen bonding was observed between the cabonyl group of SB and ARG256 residue of BSA and van der Waal forces also observed between SB and nine residues within the binding pocket of BSA. CP showed multiple hydrogen bonds between its carbonyl group and GLY247, LEU249 and LEU250 residues of BSA and SP also interacted with ARG256 of the protein via hydrogen bonding, and other amino acids via distance-dependent van der Waals forces. The study explains the binding mechanisms of the analytes with BSA and could determine their resultant pharmacodynamic effect on protein function when employed as food or pharmaceutical additives.