The lower part of Fig. shows the fragments and cap molecules that are generated by the MFCC fragmentation, i.e., amino acid fragments A to F and cap molecules AB and BC for the upper strand as well as cap molecules DE and EF for the lower strand. When calculating the MFCC total energy E MFCC tot [see Eq. ( )], the blue and red groups are each added twice and subtracted once, i.e., they are correctly included only once in the total energy.