Returning to the conventional MFCC method with ACE-NME caps, additional challenges appear when considering a two-body correction. The first problem is illustrated in Fig. for a small part of a β-sheet structure consisting of amino acids A, B, and C in one strand and D, E, and F in the other stand (see top left part of Fig. ). The peptide groups in the two strands form hydrogen bonds, one of which is highlighted in Fig. . It connects the N-H group of the peptide unit between amino acids A and B (highlighted in blue)