Fluorescence spectroscopy, molecular docking and molecular dynamic simulation studies of HSA-Aflatoxin B1 and G1 interactions

The interaction of human serum albumin (HSA) with aflatoxin B1 and G1 has been investigated by fluorescence spectroscopy, molecular docking and molecular dynamic simulation. The results of fluorescence spectroscopy demonstrated that the fluorescence emission of HSA was quenched considerably upon the addition of aflatoxin B1 and G1 through a static quenching mechanism. The thermodynamic parameters were calculated using Van't Hoff equation which indicated that the reaction is spontaneous and hydrogen bonding and van der Waals forces played a leading role in the binding of aflatoxin B1 and G1 to HSA. The binding constants of aflatoxin B1 and G1 to HSA was determined by the modified Van't Hoff equation. We have also performed molecular docking studies to locate the binding sites, binding mode and to determine of binding constants of aflatoxin B1 and G1 to the HSA. The results of molecular docking was shown that both aflatoxin B1 and G1 binds to subdomain IB of HSA mainly by hydrophobic interaction and hydrogen bonding which they are in good agreement with those obtained by fluorescence study. After performing the MD simulation, the interaction constant values obtained from the docking results were much closer to the experimental value of fluorescence spectroscopy. All the fluorescence spectroscopy, molecular docking and molecular dynamics results have a good correlation with each other.