Spectroscopic and computational approaches to investigate the binding mechanism of multi-purpose dye pararosaniline with serum albumin protein

Pararosaniline (PRN) is a significant carcinogenic threat to human, animal, and environmental health and is classified as a Category 2B carcinogen. Investigating the binding interactions of PRN with Bovine Serum Albumin (BSA) is crucial to understand the toxic effects of this carcinogenic dye within the body. This study examined the interaction between PRN and BSA using various spectroscopic techniques and computational methods. Fluorescence spectroscopy was used to determine the thermodynamic parameters required to form the complex and the stability and interactions between them were examined through molecular docking and dynamic simulations. Conformational analysis of the PRN-BSA complex was conducted through Circular Dichroism and Dynamic Light Scattering studies, corroborated by Molecular Dynamics results. The experimental results underscored the dynamic nature of this interaction, showcasing effective binding at physiological temperatures without inducing major conformational alterations in BSA structure. The stability of the complex was attributed to strong hydrophobic interactions with specific amino acid residues in subdomain IB of domain I, as well as notable van der Waals interactions between the dye and water molecules. A detailed energetic assessment of the stable complexation was monitored through MM/PBSA and QM calculations, aligning well with the experimental results. This study provides critical insights into the underlying mechanism of the interaction between PRN and BSA, which can further aid in understanding the toxic effects and potential bioavailability of similar molecules.