Functional and conformational properties of mouse hemoglobins

Hemoglobins from four strains of mice (C3H/SW, DBA/2J, C57BL6/Kh and A.TH) examined showed pH-dependent heme-heme interactions. The oxygen affinity and cooperativity are reduced at acidic pH. The oxygen equilibrium parameters increase as a function of increasing pH and at physiological pH values they are similar to the corresponding values of human hemoglobin A. The nitrosyl derivatives of these mouse hemoglobins undergo a quaternary structural transition to the T state in going from pH 7.0 to 6.0. These functional and conformational properties are indicative of destabilised oxy structures of mouse hemoglobins at acidic pH. This study also confirms that the cysteine residue at beta 13(A10) position has no influence on the oxygen equilibrium properties or conformation of the molecule.