The Binding Assessment with Human Serum Albumin of Binuclear Ni(II) and Cu(II) Complexes Containing Bidentate ۸-Hydroxyquinoline Ligand

The study of human serum albumin (HSA) binding in biophysical and biochemical studies is important sinceit has a well-known primary structure and it has been associated with the binding of many different categoriesof small molecules. Metal ions bind to proteins via coordinate bond formation with amino acid side chains.The use of metal complexes allows the formation of targeted protein-bound adducts that show binding viacoordination or noncovalent interactions. Herein, two Ni(II) and Cu(II) complexes of the general type[Ni۲(Q)۶] and [Cu۲(Q)۴] (Q = ۸-hydroxyquinoline) were synthesised and characterised by FT-IR, UV–Visand ۱H-NMR. The optimized structures and frontier orbitals properties were computed using DFT/B۳LYPmethod and LANL۲DZ and ۶–۳۱G** as basis sets. The electronic structure and spectral characterization ofthe synthesized complexes have been investigated using the density functional theory (DFT). The interactionof these complexes with protein (HSA) was followed via fluorescence spectroscopy, circular dichroism (CD)and molecular docking simulation. The observation of remarkable quenching in the emission spectrum ofHSA upon titration with the complexes with an excellent binding constant (Kb= ۹۳.۸۸ mM-۱ for [Ni۲(Q)۶])reveals the strong interaction between the complexes and HSA. Furthermore, the Kq values of thefluorescence quenching are greater than ۲.۰ × ۱۰۱۰ M−۱ s−۱, establishing the fact that the fluorescencequenching is static. Molecular docking results revealed these complexes bind with HSA, and the binding sitewas positioned in Sudlow Site II of HSA (subdomain IIB).

کلیدواژه ها:

۸-hydroxyQuinoline ، HSA Binding ، Molecular Docking ، DFT ، Circular Dichroism