Mechanistic and kinetic aspects of Natamycin interaction with serum albumin using spectroscopic and molecular docking methods

Natamycin (NT) is a polyene natural antimycotic, which has an antimicrobial effect against yeasts and molds and is used as a preservative in the food industry. In the present study, we evaluated NT interaction with bovine serum albumin (BSA) through surface plasmon resonance (SPR) and several spectroscopic techniques, which are accompanied by a molecular docking study. According to the results, the intensity of BSA fluorescence decreased by adding different concentrations of NT. The fluorescence quenching results showed that NT reduces the intensity of BSA fluorescence by forming a complex with BSA through a hybrid quenching. Binding constant decreases from 18.73 to 2.13 (102 M−1) with increasing temperature, which indicates a decrease in complex formation owing to the interaction of NT with BSA. Negative values of ΔH° and ΔS° confirmed that van der Waals forces and hydrogen bonds are the basic forces in the interaction of NT with BSA. Moreover, increasing the equilibrium constants values with increasing temperature indicated that BSA binding to NT decreased. Finally, BSA interaction occurring with NT through Ser 109, Asp 111, Lys 114, Leu 115, Glu 424, and Arg 458 have been verified via molecular docking analysis. Attained results via SPR and fluorimetry showed that the binding constant between BSA and NT decreased when the temperature was raised.