Hydrophobicity/charge plot of folded, unfolded and unclassified proteins in set C. Hydrophobicity/charge plot of proteins in set C, experimentally identified as folded (red) and unfolded (blue). Upper green triangles refer to folded proteins unclassified by S
, lower black triangles refer to unfolded proteins unclassified by S
. Note the substantial overlap of folded (red) with unfolded proteins (blue), due to the presence of a higher number of untypical folded proteins in this set with respect of set B (figure 2). Nevertheless, the centroids of the three distributions (see inset) are aligned and that of unclassified proteins is in between, indicating that the twilight zone is intermediate.