Molecular Dynamics Studies of the Hydration of α,α-Trehalose

Molecular dynamics simulations have been used to model the aqueous solvation of the nonreducing sugar α,α-trehalose. The anisotropic structuring of water around the trehalose molecule was calculated in a Cartesian coordinate frame fixed with respect to the sugar molecule by averaging water positions over the trajectories and was plotted in two and three dimensions relative to the sugar. The hydrogen bonding of this sugar to solvent was calculated and compared to other sugar solutes. Hydration was required to produce the experimental conformation, through the exchange of an internal hydrogen bond for similar bonds to solvent. This equilibrium conformation was found to impose extensive structuring on the adjacent solvent, with structuring extending out to at least the third “solvation shell”, while pure liquid water exhibits such structure only in its nearest neighbors. The details of the structuring are determined by both the specific stereochemical topology of the molecule and its conformation, with consi...