Figure 7

(A) Identification of unique n -grams in hemoglobin. The deoxy hemoglobin structure (PDB:1A3N [60]) is shown in Panel A. The tetramer is composed of two α-subunits, (white) two β-subunits (wheat) and four heme groups (red). The most unique amino acids are colored magenta (α-subunit) and cyan (β-subunit). (B, C) Scarcity scores for the respective α- and β-subunits. The scores are based on 138 and 224 homologous sequences (E value < 10^-57) retrieved for a- and b-subunits, respectively. The residues colored in panel A have scarcity scores (based on 3-grams to which they belong; see eq 5) above the threshold indicated by the orange dashed line. (D) PROSITE motifs. Two histidines (magenta) are identified at the heme binding sites using PROSITE for each subunit.