Fig. 1.—

Alignment of globins of the Chinese softshell turtle (Pelodiscus sinensis; Psi) and the western painted turtle (Chrysemys picta bellii; Cpi). The secondary structure of human Mb is superimposed in the upper row, with α-helices designated A through H, the globin consensus numbering is given below the sequences. Conserved residues are shaded (100% conservation, black; 75%, dark gray). The conserved histidine and phenylalanine residues required for oxygen binding are marked. Note that PsiHbAa harbors a glutamine instead of the histidine at helix position E7.