Including two-body contributions in the eb-MFCC-MBE(2) reduces these error significantly (see also Ref. ). For the β-strand and the turn, this is sufficient to reduce the errors to 1.1 and 3.1 kJ/mol, respectively, whereas for the 3 10 -helix and the α-helix, errors of 22.7 and 21.1 kJ/mol, respectively, remain. In the latter case, each peptide group in the center of the helix is involved to two hydrogen bonds, such that these intramolecular interactions are not fully captured by a two-body approximation.