Conformations of the glycine dipeptide

Abstract Integral equation theory is applied to the determination of the intramolecular potential of mean force for the glycine dipeptide, N ‐acetyl glycyl‐ N ‐methylamide, in aqueous solution. The solvated free energy for the dipeptide as a function of the dihedral angles ϕ and ψ (Ramachandran plot) is determined and compared with the vacuum surface. Conformations forbidden in vacuum are found to be populated in aqueous solution. The results of the glycine dipeptide are compared to a parallel study on the alanine dipeptide. Solvent effects are found to be responsible for the extent of many of glycines properties related to flexibility.