Glycine molecules in ionic liquid based reverse micelles: Investigation of structure and dynamics using molecular dynamics simulations

Abstract

Abstract Amino acids, the building blocks of proteins, are probed in reverse micellar encapsulation processes of biological molecules. To achieve a theoretical picture of the effect of confinement of amino acids on the structure and dynamics of reverse micellar aqueous core, a water/[C 1 C 10 Im][Br] reverse micelles containing variable number of glycine molecules (0 to 8), dispersed in pure nonane has been studied using atomistic molecular dynamics simulations. The size of the central water pool was found to become stable with increase in the number of glycine molecules. Glycine molecules associate together through H-bonding interaction within the aqueous core of the reverse micelles. The radial density profile of glycine molecules from the center of mass of the reverse micellar aqueous core shows the preferential presence of glycine molecules near the center. Confinement in nano-space region stabilizes the H-bonds formed between glycine molecules compared to bulk aqueous solution. Increase in the number of glycine molecules within the reverse micellar aqueous core increases the survival time of H-bonds among glycine molecules as well as among water molecules. Translational and reorientational motion of glycine and water molecules are found to be directly related to the survival probability of intermolecular glycine–glycine and water–water H-bonds suggesting the correlation between the mobility of molecules with the rearrangement of the H-bonding network.