Interaction of CRABP I with Ammonium-based Dicationic Ionic Liquids: A Biophysical Perspective

Abstract

Using a variety of spectroscopic methods, we investigated the biophysical behavior of the CRABP I protein when ammonium-based dicationic ionic liquids (ILs) were present as cosolvents. Variations in the microenvironments of aromatic amino acid residues were discovered via fluorescence analysis. With a red shift, the fluorescence intensity showed a quenching behavior as the cosolvent content rose. The synchronous investigation likewise showed a similar pattern. While the binding investigation using temperature-dependent fluorescence demonstrated an electrostatic connection between the protein and ILs, the Stern Volmer analysis demonstrated the static behaviour of quenching. Circular dichroism showed that the protein's secondary structure was distorted to some extent. The spectroscopic results were validated by a molecular docking analysis which showed the electrostatic interactions of ILs with different aminoacid residues of protein.