Experimental and molecular docking studies in understanding the biomolecular interactions between stem bromelain and imidazolium-based ionic liquids

The present study reports the influence of imidazolium-based ILs such as 1-butyl-3-methylimidazolium hydrogen sulphate [C(4)mi](+) [HSO4], 1-butyl-3-methylimidazolium acetate [C(4)mi](+)[CH3COO](-) and 1-butyl-3-methylimidazolium nitrate [C(4)mi](+)[NO3](-) on the structural and thermal stability of cysteine proteinase enzyme-stem bromelain (BMN) by employing several biophysical techniques. This work is intended to study the action of various anions and concentration of ILs on the structural stability of BMN. The results reveal that all the ILs acted as stabilizers at lower concentrations such as 0.01 and 0.05 M. Moreover, we have also tried to unveil the type and different existing interactions between BMN and the cation and anions of ILs using molecular docking studies. The results show that the stability of BMN is dependent of the nature of ions of ILs and their concentration, the ILs are supposed to alter the properties of the protein by the mechanism of their interaction with the functional groups present on the surface of protein. (C) 2019 Elsevier B.V. All rights reserved.