For the solvated polypeptides, we used a simple QM/MM setup with electrostatic em-bedding, in which the coordinates of the solvent molecules were kept fixed. All solvent molecules were modeled classically as TIP3P point charges with a Lennard-Jones potential. We used atom-specific Lennard-Jones parameters by Freindorf and Gao, which have been optimized for QM/MM geometry optimizations based on the TIP3P model .