Intermolecular investigation on interaction of two ternary copper(II) Schiff base complexes with bovine serum albumin

This study was conducted to investigate the mechanism of the interaction between bovine serum albumin (BSA) and two ternary copper (II) Schiff base complexes by means of various spectroscopic techniques and molecular docking calculations. The results showed that both Schiff bases could effectively quench the endogenous fluorescence of BSA, forming 1:1 complexes and static quenching procedure due to the formation of the Schiff base-BSA complexes. Fӧrster energy transfer measurements, synchronous fluorescence spectroscopy, and docking studies showed that both Schiff bases bind to the tryptophan residues of BSA in short distances. Molecular docking results showed that both Schiff bases were bound in the hydrophobic cavity of BSA and were surrounded by active amino acid residues via forming several hydrogen and van der Waals bonds. Furthermore, as shown by the synchronous fluorescence and Fourier transform infrared spectroscopy, both Schiff bases could lead to the conformational changes of BSA, which might affect its physiological function.