Investigation on bindings of a binaphthoquinone derivative with serum albumin proteins by fluorescence spectroscopy

Abstract

Binding of a binaphthoquinone derivative namely, 5a,5b-dimethyldibenzo[b,h]biphenylene-5,6,11,12(5aH,5bH,11aH,11bH)-tetraone (L, C₂₂H₁₆O₄)  with bovine serum albumin (BSA) and human serum albumin (HSA) have been examined by using fluorescence spectroscopy. The fluorescence emission of the L is quenched upon addition of L to a solution of  BSA or that of HSA, but the BSA has shown a higher affinity towards L over  the HSA protein. A molecular docking study is also performed to suggest the sites of BSA  for weak interactions to bind the L. The docking analysis,  has revealed the N-H···O  hydrogen bonds of L with different  amino acid residues. The L is located at about 7.7Å  away from the Trp-213 which is the fluorescent unit of the BSA suggesting the role of environment of the tryptophan residue to be an important to have changed the emission intensities.