Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

The interaction between Bovine Serum Albumin (BSA), one of the standard proteins used to study the bioavailability of biological molecules in the bloodstream, and allura red, a commercial food additive, was studied by molecular docking. The computational results suggest GoldScore as the main function to study the BSA:Allura red interactions. The most probable binding site to Allura red is the site IIA (Sudlow’s site I), where Trp212 residue can be found and the Student's t-distribution indicate that there are statistically significant differences between the two data sets obtained by molecular docking. The molecular docking results suggest that Allura red interacts with Arg-194, Arg198, Trp-212, Arg-217, Gln-220, Lys-294 and Ser-343 residues, by different intermolecular interactions (electrostatic forces, hydrogen bonding and hydrophobic interactions). After semi-empirical optimization, the amino acid residues Gln-220 and Lys-294 exhibited a significantly different interaction structure with Allura red. Theoretical interaction enthalpy change value (ΔHint=14.0 kJ/mol) reinforces the proposal that the preferential interaction cavity for Allura red in BSA is the Trp-212containing site