Characterization of the interaction between farrerol and bovine serum albumin by fluorescence and circular dichroism

The binding of farrerol to bovine serum albumin (BSA) in aqueous solution was investigated by fluorescence quenching spectra, synchronous fluorescence spectra, circular dichroism (CD) and the three-dimensional (3D) fluorescence spectra at pH 7.40. The results of fluorescence titration indicated that farrerol could quench the intrinsic fluorescence of BSA in a static quenching way. The cause of showing upward curvy patterns in Stern–Volmer plots was analyzed. The binding sites number n and binding constant K using fluorescence quenching equation at 310 K were calculated. The binding distance and the energy transfer efficiency between farrerol and BSA were also obtained according to the theory of Förster's non-radiation energy transfer. The effect of some metal ions on the binding constant of farrerol with BSA was also studied. The effect of farrerol on the conformation of BSA was analyzed using CD, synchronous fluorescence spectra and three-dimensional (3D) fluorescence spectra under experimental conditions. Furthermore, the fluorescence displacement experiments indicated that farrerol could bind to the site I of BSA.

Graphical abstractThe interaction between farrerol and bovine serum albumin (BSA) was studied by fluorescence and circular dichroism (CD). The quenching mechanism, binding constants, and binding distance were obtained.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Stern–Volmer plots showed upward curvy patterns. ► The binding of farrerol to BSA causes the structural change of BSA. ► The presence of metal ions is of great importance in pharmacy, pharmacology. ► The binding constants, binding sites and binding distance were calculated.