Fig. 2

3D models of the globins found in the different species studied, with their heme group. a The B. symmytilida model was obtained based on L. terrestris Hb structure; residues under positive selection are labeled in white (27V, 30A, 52Q and 65C). b The B. reveeana model is based on the tertiary structure of S. inaequivalis Hb; the residue under positive selection is shown (31G). c Ascaris D2 model was built based on the di-domain, D1 crystal (1ash); residue under positive selection on D1 is depicted (11A), name of the residues with possible interactions with amino acid in position 11 are shown in grey. A comparative scenario is presented for Ascaris D1 and D2 with the interacting residues being in equivalent positions in the protein tertiary structure. Helices are represented in a color spectrum depicting helix A in blue all through helix H in red. Depicted residues are colored by element; OH: red; NH: blue: C: helix color. Heme group is shown in light grey. See “Methods” and “Results” sections for detailed information.