Biophysical characterization of human serum albumin interaction with dapagliflozin: multi-spectroscopic and molecular docking study

Abstract

Human serum albumin (HSA) is the most abundant protein in human blood plasma and plays a crucial role in drug transport and pharmacokinetics. Dapagliflozin (DAPA), a sodium-glucose co-transporter 2 (SGLT2) inhibitor, is widely prescribed for the treatment of type 2 diabetes mellitus. In the present study, we employed a combination of multi-spectroscopic techniques, including fluorescence spectroscopy (three-dimensional, synchronous), UV-visible absorption spectroscopy, thermodynamic analysis, and molecular docking to investigate the interaction of dapagliflozin with HSA under physiological condition. The quenching mechanism of DAPA was determined to be dynamic through Stern-Volmer and modified Stern-Volmer analyses. The binding constants at 298 K, 303 K, 308 K were 0.52x104, 0.303x104 and 0.264x104 M-1, respectively. Thermodynamic analysis revealed that the binding process is spontaneous, driven primarily by hydrogen bonding and hydrophobic interactions at various temperatures. Synchronous fluorescence studies suggest that DAPA binding does not significantly alter the microenvironment around the tyrosine and tryptophan residues of HSA, implying that the binding sites are spatially distinct from these residues. Three-dimensional fluorescence studies reveal that the addition of DAPA to HSA affects changes in the micro-environment and conformation of HSA. UV-VIS spectroscopy confirmed the formation of the HSA-DAPA complex, characterized by spectral shifts in both peptide bond and aromatic amino acid regions, indicating alterations in the protein\u27s secondary structure. The decrease in zeta potential upon DAPA binding suggests a change in the surface charge and potential conformational changes in HSA, which may influence its biological activity and interaction with other molecules. Molecular docking studies identified key amino acid residues involved in the binding of DAPA to HSA, primarily through hydrophobic and hydrogen bond interactions