Spectroscopic studies of the aggregation behavior of Human Serum Albumin and cetyltrimethylammonium bromide

To check the role of micelle in the interaction studies of human serum albumin (HSA) and cetyltrimethylammonium bromide (CTAB), many spectroscopic techniques, like UV–visible, fluorescence, circular dichroism, fluorescence lifetime measurement, and atomic force microscopy (AFM), are employed. The binding affinity of all compound groups depended on the hydrocarbon chain, indicating the predominant role of hydrophobic forces, electrostatic forces and supported by polar interactions on protein surfaces. The protein has a different effect on the polarity of a microenvironment in fluorescence spectra above and below the critical micelle concentration (CMC) of the suractant. The far-UV-CD spectra show unfolding below the CMC and refolding above the CMC. The binding of the surfactant induces changes in the microenvironment at different pHs around the residues of the aromatic amino acid and the disulfide bond of protein. The AFM images show significant changes in the protein's structure. AFM images show dense aggregation below the CMC and above the CMC, some net-like structure formed in the HSA-CTAB complex. To test the experimental results, we used Auto dock Vina to conduct molecular docking. Above and below the CMC, structural changes can be seen. In HSA and CTAB interaction CMC plays an important role and Binding interaction will change after and before the CMC. [Display omitted] •The study shows the interaction between HSA and CTAB at three different pHs.•HSA begins to aggregate the denaturation rate sequentially, following the CMC.•Lifetime indicates the aggregation frequency is higher above the CMC.•AFM images show the structural changes in protein at above and below the CMC.•CMC plays an important role in controlling the protein's aggregation.