Primary structure of alpha-globin chains from river buffalo (Bubalus bubalis) hemoglobin.

Primary structure analysis of the four river buffalo alpha-globin chains showed that haplotypes A andB differ from each other by a substitution at codon 64 that may encode Ala or Asn. The A haplotypeencodes two a-globin chains, Ia1 and IIa3, which differ at positions 129 and 131: Ia1 has64 Ala, 129 Phe, 131 Asn; IIa3 has 64 Ala, 129 Leu, 131 Ser. The B haplotype encodes two a-globinchains, Ia2 and IIa4, which differ at positions 10 and 11: Ia2 has 10 Ile, 11 Gln, 64 Asn; IIa4 has10 Val, 11 Lys, 64 Asn. Apart from the Ala/Asn polymorphism at position 64, amino acid substitutionsin allelic and nonallelic a-globin chains seem to have arisen by single point mutations. Detectionof electrophoretically silent mutations due to neutral amino acid substitutions and their influenceon the isoelectric point are discussed. Furthermore, primary structures of river buffalo a-globinchains are compared to other species of the Bovidae family to suggest evolutionary events that havecharacterized the amino acid substitutions of river buffalo hemoglobin.