Study of the interaction between 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitril and bovine serum albumin by fluorescence spectroscopy

A new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN), was synthesized. The interaction between bovine serum albumin (BSA) and DHPEPN in Tris–HCl buffer solution (pH 7.4) was investigated using fluorescence and UV–vis absorption spectroscopy. The mechanism of BSA fluorescence quenched by DHPEPN is discussed according to the Stern–Volmer equation. The binding constant and the thermodynamic parameters ΔH, ΔS, ΔG at different temperatures were calculated. The results indicate that the van der Waals interaction and hydrogen bonding play major roles in the binding process. The distance between BSA and DHPEPN is estimated to be 3.59 nm based on the Förster resonance energy transfer theory. The spectral changes of synchronous fluorescence and three-dimensional fluorescence suggest that both of the microenvironment of DHPEPN and the conformation of BSA are changed during binding between DHPEPN and BSA.

Graphical abstractA new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN) is synthesized and used as fluorescent probe for protein. With increasing the amount of BSA, the fluorescence intensity of DHPEPN was enhanced and emission band slightly blue shifted. At the same time a good linear response of fluorescence intensity as a function of BSA concentration was obtained.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN), was synthesized and characterized by 1H NMR, IR, and mass spectrometry data. ► The interaction between DHPEPN and bovine serum albumin was investigated using fluorescence and UV–vis absorption spectroscopy. ► The binding constant and the thermodynamic parameters ΔH, ΔS, ΔG of the binding process between DHPEPN and bovine serum albumin were calculated.