Amino acid sequence of Kalinowaski's Tinamou (Nothoprocta kalinowskii) hemoglobin and the rate of evolution of bird αD-globin

Two hemoglobin components are recognized in erythrocytes of the adult Tinamou. We determined the amino acid sequences of Tinamou alpha(D)-, alpha(A)-, and beta-globins from intact globin chains and several chemically cleaved fragments. A remarkable feature of Tinamou hemoglobin was a deletion in the alpha(D)-globin chain. This has not been reported in the literature, except in pigeon embryonic alpha(D)-globin. The amino acid sequences of Tinamou globin were highly similar to those of Ostrich and Rhea hemoglobin. Comparison between Tinamou, Ostrich, and Rhea that suggested the evolution speed of globin, alpha(D) = alpha(A) > beta, was related with the early appearance birds. The important residues in Tinamou hemoglobin as the heme contact and oxygen binding regions were highly conserved in other species.