Implications of Imidazolium based Ionic Liquids as Refolding Additives for Urea-induced denatured Serum Albumins

One of the major challenges in protein stability is that proteins can easily unfold in the presence of denaturants like urea, which alters the native structure of proteins. There are numerous studies in which ionic liquids (ILs) act as promising biocompatible solvents (Bio-IL) for biomolecules. In this context, we present the refolding ability of a biocompatible imidazolium-based ionic liquid, 1-ethyl 3-methyl imidazolium ethyl sulfate [Emim][ESO4] (IL-1) and 1-ethyl 3-methyl imidazolium chloride [Emim][Cl] (IL-2) against the chemically induced structural changes in bovine and human serum albumin (BSA and HSA). The work is substantiated with several spectroscopic, thermal and docking studies. In steady-state fluorescence spectroscopy, we observe that the emission intensity quenches for the protein in urea which is reversible with the addition of ILs. Circular dichroism spectral studies reflect the reappearance of α helical content which is a good indicator of the refolding ability of ILs. Further, thermal...