Primary structure of hemoglobin alpha-chain of Columba livia (gray wild pigeon).

Primary structure of hemoglobin of alpha-chain of Columba livia is presented. The separation of alpha-chain was obtained from globin by ion-exchange chromatography (CMC-52) and reversed-phase HPLC (RP-2 column). Amino acid sequence of intact as well as tryptic digested chain was determined on gas-phase sequencer. Structure is aligned homologously with 21 other species. Among different exchanges, positions alpha 24 (Tyr----Leu), alpha 26 (Ala----Gly), alpha 32 (Met----Leu), alpha 64 (Asp----Glu), alpha 113 (Leu----Phe), and alpha 129 (Leu----Val) are unique to pigeon hemoglobin. The various exchanges in alpha-chain are discussed with reference to evolution and phylogeny. The results show that the order Columbiformes is evolutionarily closer to the order Anseriformes. Since the pigeon is homogeneous, having HbA (alpha A-chain) and lacks alpha D-chain, its phylogenetic placement could be established among birds having single hemoglobin components.