Ramachandran free-energy surfaces for disaccharides: trehalose, a case study Original Research Article

We present calculated potential of mean force surfaces for rotation about ϕ, ψ dihedral angles of the α(1↔1)α-glycosidic linkage in the disaccharide trehalose (α-d-Glc-(1↔1)-α-d-Glc) in both vacuum and aqueous solution. The effects of aqueous solvation upon the α(1↔1)α-glycosidic linkage are investigated through comparison of the vacuum and aqueous solution free-energy surfaces. These surfaces reveal that trehalose is restricted to a single minimum-energy conformation in both vacuum and solution. The exceptional rigidity of this disaccharide in solution may provide a molecular rationale for the antidesiccant properties of trehalose glasses.