Molecular spectroscopic and docking analysis of the interaction of fluorescent thiadicarbocyanine dye with biomolecule bovine serum albumin

Binding studies of the water-soluble thiadicarbocyanine dye 3,3'-diethylthiadicarbocyanine acetate (DTC) with bovine serum albumin (BSA) were examined under physiological conditions using spectroscopic techniques like fluorescence, UV-Visible, circular dichroism (CD), FT-IR and molecular docking methods. Compiled experimental results envisage that DTC quench the fluorescence intensity of BSA. The increasing binding constants (K) were found to be in the order of 10(3) Mol(-1) as a function of temperature, as calculated from the fluorescence quenching data. The quenching mechanism, thermodynamic parameters (Delta H-0, Delta S-0 and Delta G(0)) and the number of binding sites have been explored. CD values showed that the secondary structure of the BSA has been altered upon binding to DTC. Displacement experiments were carried out with different site probes to find out the binding site of DTC on BSA and it was found that binding interaction at site II of sub-domain IIIA. The interference of common metal ions on the interaction of DTC with BSA has also been studied. The experimental data exhibit that DTC interacts with BSA by hydrophobic forces. The experimental findings from BSA binding studies were validated by using in silico molecular docking technique. The results of the investigations were accurately supported by studies on molecular docking. The optimal shape of the molecular probe demonstrated the affinity as a free binding energy release of -7.37 Kcal/mol. The present research report endeavors to the approachable nature of water-soluble DTC dye and paves way for targeted biological interactions.Communicated by Ramaswamy H. Sarma

Automated summary

This study investigated the binding characteristics of the water-soluble thiadicarbocyanine dye DTC with BSA using spectroscopic techniques and molecular docking methods. The experimental results showed that DTC quenched the fluorescence intensity of BSA and altered its secondary structure. The binding was found to be driven by hydrophobic forces. Molecular docking validated the experimental findings and revealed a free binding energy release of -7.37 kcal/mol. This research provides insights into the interaction between water-soluble DTC dye and biological molecules.