Prosimian Hemoglobins I. The Primary Structure of the β-Globin Chain of Lemur Catta

Abstract

The primary structure of the β chain from the hemoglobin of a prosimian primate, Lemur catta, has been determined by automated Edman degradation of intact polypeptide chain and fragments produced by tryptic, cyanogen bromide and acid cleavage, and by homology with the sequence of Lemur fulvus. The sequence presented here differs from the human β-globin sequence at 26 sites. This is the same degree of divergence previously reported for the β-globin chain of Lemur fulvus. The sequences of the two congeneric lemuroid β-globin chains are surprisingly divergent, differing at 18 sites. Of the 26 positions where L. catta differs from Homo sapiens, 7 are at positions with defined function. Of these 7 positions, 4 (2-Phe, 54-Ile, 94-Val, 112-Ile) are unique to L. catta among the primate β-globin chains of established sequence. Residue 112-Ile is consistent with the prediction of Beard and Goodman (19) of an isoleucyl residue in this position in the ancestral primate β-globin chain.