(188cq) Molecular Dynamics Simulations of Protein Refolding in Deep Eutectic Solvents

Deep Eutectic Solvents (DESs) are eutectic mixtures composed of different cations and anions of Lewis and Bronsted acids and bases.With their favorable properties such as low volatility, biodegradability, low cost, simple synthesis, etc., they are considered as green media and sustainable replacements of ionic liquids to carry out varieties of chemical and biochemical processes ^[1]. One amongst many promising applications of DESs is maintaining the structure of protein in the absence of water. Experiments on different proteins in DESs and their aqueous solutions have shown that the secondary and most of the tertiary protein structure is maintained in the DESs and that refolding can also be achieved in aqueous DESs solutions ^{[2], [3]}. However, the experiments are limited and the intermolecular interactions between the solvents and protein are obscured. To this end, we perform molecular dynamics simulations of lysozyme in its native structure in the presence of three different DESs; (i) urea and choline chloride, (ii) glycerol and choline chloride, and (iii) arginine and choline chloride. The first two DESs are chosen as in the experimental studies, whereas arginine-based DES is chosen because of arginine’s ability to assist in protein refolding ^[4]. Furthermore, the simulations are carried on the protein unfolding and refolding process in the presence of these DESs and their aqueous solutions. The interactions between the solvents and the protein are evaluated in terms of interaction energies and hydrogen bonding patterns. Protein structure is studied in the form of its deviation from the native structure. The results suggest stability of the secondary structures of the protein in the presence of the DESs.

References:

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