The Amino-Acid Sequence of Northern Mallard(Anas platyrhynchos platyrhynchos)Hemoglobin

Abstract

The complete amino-acid sequence of the major Hb component (HbA) of the adult Northern Mallard (A. platyrhynchos platyrhynchos) is presented. A minor component HbD was also detected but in low concentrations. The sequences of .alpha.A-and .beta.-chains were established by automatic Edman degradation on tryptic peptides and peptides obtained by specific chemical cleavages. The alignment of the peptides was performed by comparison with the .alpha.A- and .beta.-chains of Greylag Goose Hb (Anser anser). Thereby an exchange of 5 positions in the .alpha.A-chains and 3 in the .beta.-chains was observed. No exchanges were found in the surroundings of the heme, in .alpha.1.beta.2-contact points, or allosteric regulatory sites. In the .alpha.1.beta.1-subunit interface 1 amino-acid residue in .alpha.A-chains and 1 in .beta.-chains are exchanged. By comparison with the amino-acid sequence derived from globin genes of domestic Duck (A. platyrhynchos), the .alpha.A-chains differ by 2 exchanges in the N-terminal region and the .beta.-chains by 5 exchanges in the C-terminal region. The comparison of the amino-acid sequence derived from .alpha.A-globin gene of the Moscovy Duck (Cairina moschata) and .alpha.A-chains of the Northern Mallard, shows only 1 replacement.