Conformers of Zwitterionic Glycine in Aqueous Phase

Abstract

Zwitterionic glycine was investigated for its major conformers and their isomerizations in aqueous phase by QM/MM‐MD. The rotameric barrier of zwitterionic glycine along C−C bond is approximately 2 kcal/mol higher than that of non‐ionized one. It can be attributed to the strong electrostatic effects of zwitterion, which attracts water solvents more tightly. Unlike the previous quantum mechanical calculations, our QM/MM‐MD found that only the gauche conformer as stable minima along the C−N bond rotation. Overall, the preferred conformers in real solution are different from those found with limited clusters, necessitating the use of QM/MM‐MD.