Molecular Docking and Spectroscopic Study on the Interaction of Serum Albumin with Iron(III) Diamine Sarcophagine

Abstract

Iron(iii) diamine sarcophagine (DiAmsar) has attracted great attention in biological and medical applications. In particular, for any potential in vivo application, knowledge about the interaction of iron(iii) DiAmsar with serum albumin is crucial. As a step towards the elucidation of the fate of iron(iii) DiAmsar introduced into an organism, first, iron(iii) DiAmsar was synthesised and characterised. In the next step, interactions of iron(iii) DiAmsar with human serum albumin (HSA) and bovine serum albumin (BSA) were systematically investigated by various spectroscopic methods (Fourier-transform infrared, UV-visible, fluorescence) and cyclic voltammetry and molecular docking techniques under simulated physiological conditions. The fluorescence intensities of HSA and BSA decreased remarkably with increasing concentration of iron(iii) DiAmsar. The Stern–Volmer quenching constant KSV at different temperatures and corresponding thermodynamic parameters such as ΔHo, ΔGo, and ΔSo were calculated. The binding distance of iron(iii) DiAmsar with HSA and BSA was also determined using the theory of fluorescence energy transfer. Further, the conformational changes of HSA and BSA induced by iron(iii) DiAmsar were analysed by means of Fourier-transform (FT)-IR. In addition, molecular docking was performed to explore the possible binding sites and the microenvironment conditions around the bound iron(iii) DiAmsar.