Photophysical and Spectroscopic Insights into the Interaction Mechanism of Azo-Ester Dye with Ovalbumin: A Molecular Docking Perspective

In this work, an azo-ester dye with phenol blocked isocyante and N,N'-dialkanol groups at the ends were studied as fluorescent probe for protein detection. The photophysical properties of the azo-ester dye were characterized both in its unbound state and in the presence of a globular protein like ovalbumin. Upon increasing concentrations of ovalbumin, a significant enhancement in fluorescence intensity was observed, indicating strong interaction between the dye and the protein. The formation of a 1:1 host-guest complex was further supported by competitive binding experiments using hydrogen-bonding molecules such as urea and guanidine hydrochloride (GuHCl), which disrupted the dye-protein complex and led to the formation of solute-protein hydrogen-bonded interactions instead. Molecular docking studies provided the additional insight into the binding mechanism, revealing a negative docking score for the dye-ovalbumin complex, attributed to hydrogen bonding, π–π stacking and multiple hydrophobic interactions. These findings suggest that the dye binds strongly to ovalbumin and may play a role in modulating its activity, highlighting potential applications in therapeutic strategies and cancer prevention.