Physicochemical responses of lysozyme on interaction with the ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] in aqueous phosphate buffer medium

This study entails physicochemical responses of lysozyme on interaction with the ionic liquid, [BMIM] [BF4] in phosphate buffer medium at pH 6 and 8. Methods used for evaluation were UV-vis and fluorescence spectroscopy, circular dichroism, and molecular docking. Interaction of the ionic liquid (IL) with the tryptophan moieties in the protein was monitored to understand the interaction features of the IL-lysozyme combine. The process thermodynamics were evaluated from the fluorescence spectral data. The interaction was observed to occur in stages, and was pH dependent. The structural changes in the interaction process like alpha-helix to random coil transition, and beta-sheet forms were also found from CD spectral results. Molecular docking was done to get information on the location of the interacted [BMIM] [BE4] in the enzyme. Such studies are not commonly found in literature. (C) 2017 Elsevier B.V. All rights reserved.