Investigation of the Interaction of Chrysene and Bovine Serum Albumin by Multispectroscopic Method

The interaction mechanisms of chrysene with bovine serum albumin (BSA) were studied by multispectroscopy and molecular docking method. The quenching mechanism, binding constants, thermodynamic parameters and binding force of chrysene with BSA were investigated. The results indicated that the fluorescence of BSA was quenched by chrysene through a static quenching procedure. The binding constants K-b and number of binding sites n were 3.97 x 10(4) M-1 and 1.0 at 298 K, respectively, which indicated that the binding of chrysene and BSA was moderate and there was one main binding site in BSA for chrysene. The thermodynamic parameters including entropy change (Delta H) and enthalpy change (Delta S) were 40.2 kJ mol(-1) and 223.0 J mol(-1) K-1, respectively, which revealed that the main binding force of chrysene to BSA was hydrophobic interaction. This result was in accordance with the results from the molecular docking. The binding distance r was 2.60 nm, which suggested that the energy transfer from BSA to chrysene occurred with high possibility. The results of synchronous fluorescence spectra, three-dimensional fluorescence spectra and circular dichroism spectra indicated that the binding of chrysene to BSA induced conformation changes of BSA.