Abstract
In this article, we have used circular dichroism (CD) and fluorescence to study the physicochemical behaviour of a β-sheet protein, CRABP I, in the presence of ammonium-based ionic liquids (ILs) as a co-solvent. From fluorescence spectroscopy, a rise in intensity was observed in the presence of ionic liquids in the micromolar range, but a reversal in fluorescence intensity at higher concentrations (millimolar range). The microenvironment of aromatic amino acids, tyrosine (Tyr) and tryptophan (Trp), have been compared using synchronous fluorescence data, and the results demonstrate a similar trend in both cases as it has been seen in steady-state spectra. By using CD spectroscopy to examine conformational behaviour, we found that the protein's secondary structure hardly changes at all. Functionality test showed marginal changes in secondary structure of the protein in the presence of ionic liquids. Binding study revealed the contribution of van der waal’s interaction in the case of N2, N4 and N6 and hydrophobic force in the case of N8. The computational study demonstrated that these biophysical behaviours can be accounted for by the hydrophobic interactions between proteins and ionic liquids.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call