Characterization of intermolecular interaction between cyanidin-3-glucoside and bovine serum albumin: Spectroscopic and molecular docking methods

The intermolecular interaction between cyanidin-3-glucoside (Cy-3-G) and bovine serum albumin (BSA) was investigated using fluorescence, circular dichroism and molecular docking methods. The experimental results revealed that the fluorescence quenching of BSA at 338nm by Cy-3-G resulted from the formation of Cy-3-G-BSA complex. The number of binding sites (n) for Cy-3-G binding on BSA was approximately equal to 1. The experimental and molecular docking results revealed that after binding Cy-3-G to BSA, Cy-3-G is closer to the Tyr residue than the Trp residue, the secondary structure of BSA almost not change, the binding process of Cy-3-G with BSA is spontaneous, and Cy-3-G can be inserted into the hydrophobic cavity of BSA (site II') in the binding process of Cy-3-G with BSA. Moreover, based on the sign and magnitude of the enthalpy and entropy changes (Delta H-0 = -29.64 kcal/mol and Delta S-0 = -69.51 cal/mol K) and the molecular docking results, it can be suggested that the main interaction forces of Cy-3-G with BSA are Van der Waals and hydrogen bonding interactions. Copyright (C) 2013 John Wiley & Sons, Ltd.