Interaction of 4'-Hydroxychalcone with Bovine Serum Albumin and Human Serum Albumin: A Fluorescence and Molecular Docking Study

Abstract

In this work, the interaction of 4^'-hydroxychalcone (4^' HC) with bovine serum albumin (BSA) and human serum albumin (HSA) was compared by using steady state absorption and fluorescence spectroscopy, FTIR, circular dichroism and molecular docking. The most abundant protein found in blood plasma is serum albumins having many physiological functions. They are mainly responsible for the absorption, distribution and metabolism of endogenous and exogenous ligands. Bimolecular quenching constants and Stern-Volmer analysis show that BSA exhibits static quenching. However, both static and dynamic quenching mechanisms are responsible for the fluorescence quenching of HSA. Absorption spectroscopy provides additional evidence of the formation of the ground state complex.  The interaction of 4'HC with BSA is stronger than with HSA. FRET study shows the possible energy transfer between 4'HC with BSA and HSA. The binding site of the protein was identified by molecular docking study. Stern-Völmer analysis of the quenching data indicates that the mechanism of quenching for BSA is static quenching and in case of HSA is dynamic quenching. Both of the serum albumins have undergone conformational change, according to the FTIR and CD analyses. According to the thermodynamic analysis, the association of BSA and HSA with 4'HC is spontaneous, enthalpy driving, and involves electrostatic force of interaction.