Structural Comparison of Polymorphic Hemoglobins of Deer with Those of Sheep and Other Species

Abstract

Abstract The structure of deer hemoglobin III, associated with sickling of the erythrocytes of Florida white tailed deer, is compared with that of deer hemoglobin V, the presence of which precludes sickling of erythrocytes under appropriate conditions, by peptide mapping and amino acid analysis techniques. Peptide mapping techniques, including combined specific color reactions, have been utilized to relate hemoglobin peptides in the deer hemoglobins to those of several species for which the amino acid sequence is known. Certain structural regions of the α and β polypeptide chains of deer hemoglobin are closely homologous to the corresponding regions in the α and β chains of these other species, as illustrated by a graph based upon the peptide mapping studies and known sequences. The tryptic peptide mapping pattern of the α chains of deer hemoglobins III and V is nearly identical with that of the sheep α chains from the three polymorphic sheep hemoglobins. In contrast to the similarity of the α chains of these two species, the β chains exhibited numerous inter- and intraspecies differences. However, the marked variations of the β chains among the polymorphic hemoglobins of the ruminants are largely confined to distinct regions of these β chains. Although the significance of a linear comparison of the homologous regions is not apparent, the relationship of these regions is clarified by use of a three-dimensional model.