Interaction between tigecycline and human serum albumin in aqueous solution

The interaction between tigecycline (TGC) and human serum albumin (HSA) in aqueous solution was investigated by fluorescence, UV–Vis spectroscopic and molecular docking methods under physiological conditions. Results of UV–Vis and fluorescence spectroscopy showed that the fluorescence quenching of HSA was a result of the formation of HSA–TGC complex. The binding constants ( K a ), binding sites ( n ), and the corresponding thermodynamic parameters (∆ H , ∆ S , and ∆ G ) of the interaction system were calculated. Thermodynamic parameters revealed that the binding process is spontaneous and the hydrophobic interactions were the main force to stabilize the complex. The distance r between the donor (HSA) and acceptor (TGC) molecules was obtained according to Förster’s theory of non-radiation energy transfer. Furthermore, the effect of some metal ions (Ca 2+ , Cu 2+ , and Fe 3+ ) on the binding constants between TGC and HSA was examined. Finally, the binding of tigecycline to HSA was modeled using the molecular docking method. Graphical abstract