(435d) Distinct Effect of Water on Solvation and Structure of Lipase in Deep Eutectic Solvents Containing Protein Destabilizer and Stabilizers

Aqueous deep eutectic solvent (DES) solutions emerge as new media for biocatalysis. The design of aqueous DES solution needs us to better understand how the effect of water on the properties of enzymes in DES relates to the DES composition. To shed light on this question, we investigate the solvation, structure and dynamics of a lipase protein in two DESs containing protein destabilizer (choline: urea (1:2)) and stabilizer (choline: glycerol (1:2)) and their aqueous solutions using molecular dynamics simulations. The properties of the lipase protein in the pure aqueous solution are analyzed as the reference. The simulation results show the distinct effect of water molecules on the active site of the lipase protein in the two DESs though the presence of water molecules adjusts the solvation shell of the lipase protein in a similar manner. For both DESs, adding water molecules weakens the DES-protein hydrogen bonds without replacing DES compounds from the solvation shell of the protein. However, adding water molecules decreases the surface area of the active site in the DES containing urea while increasing the surface area of the active site in the DES containing glycerol. The amino acid residues on the active site also present different variations in the two DESs upon the adding of water molecules.