Biophysical approaches of human serum albumin upon interaction with a curcumin derivative

Human serum albumin (HSA) is one of the most abundant blood proteins. It serves as a transport protein for several endogenous and exogenous ligands as well as various drug molecules [1]. In addition, the levels of this protein in tumor cells are much higher than normal cells, and acts as carrier conjugate of many antitumor drugs [2]. Therefore, interaction studies of HSA to comprehension of the pharmacokinetics of drugs and the function of HSA would be interesting [3].In the current study, the interaction between HSA and curcumin derivative (DVH) was systematically investigated in details for the first time by UV-Vis absorption, fluorescence and circular dichroism methods. The results proved that the DVH could slightly change the secondary structure of protein. Fluorescence spectroscopic studies demonstrate that DVH binds to HSA through a static quenching mechanism. The binding constant (Kb) and the number of binding sites (n) were obtained based on the results of fluorescence measurements. The results of site marker investigations showed that DVH is embedded into subdomain IIA of HSA. The thermodynamic parameters indicate that the binding process was spontaneous and that hydrogen bonds and van der Waals forces play a major role in the interaction. Furthermore, the apparent distance between donor (HSA) and acceptor (DVH) was determined using fluorescence resonance energy transfer (FRET). The obtained results give us key insights into the performance of effective anti-cancer drugs when faced with proteins such as HSA.

Keywords:

Human serum albumin , Curcumin , 3D florescence , Thermodynamic , FRET