The structure of goat hemoglobins: IV. A third β chain variant ( βE) with three apparent amino acid substitutions

The presence of a third type of hemoglobin β chain, termed β E, in nonanemic domestic goats is reported. Structural analyses showed that this β chain differs from the β A chain at a minimum in three amino acid residues, namely, the replacement of a Glx (likely glutaminyl) residue by a histidyl residue in peptide T-10, a lysyl residue by an arginyl residue in peptide T-11, and a leucyl residue by a valyl residue in peptide T-13. All available evidence indicates that the structural gene producing the β E chain is allelic to the gene producing the β A chain. Thus, the variance in the structure of goat hemoglobin β E chain is likely the result of an allele with multiple replacements at a single Hb β structural locus.