The discriminant weight of the descriptors for pairs (R, R), (R, P), (P, R) and (A, R) with different lg values are shown in Figure 2B. As indicated by the figure, the descriptor with lg of 4 for pair (R, R) has the highest discriminant power. For pair (R, P) and (P, R), the discriminant weight of all descriptors are slightly different. In case of pair (A, R), the descriptor with lg of 5 is the most discriminative feature. In conclusion, for an amino acid pair, the distance between the two amino acids along the sequence can impact its discriminant power in DNA-binding protein identification.