Hemoglobin M: effect of the proximal or distal histidine replacement on circular dichroism in the visible region.
To examine the effects of a replacement of the proximal or the distal histidine on the structure of hemoglobin (Hb), absorption and circular dichroic (CD) spectra of five species of Hbs M in the visible region were measured. Four Hbs M had a characteristic but a similar absorption spectrum upon amino acid substitution, however, the proximal histidine replaced Hbs M (Hb M Iwate and Hb M Hyde Park) showed considerably different CD spectra from those of the distal histidine replaced ones (Hb M Boston and Hb M Saskatoon). The former exhibited large positive CD but the latter gave a complex CD spectrum with positive and negative extrema. On the other hand, absorption and CD spectra of Hb M Milwaukee did not changed very much from those of Hb A.
D002942:Circular Dichroism; D006449:Hemoglobin M; D006455:Hemoglobins, Abnormal; D006639:Histidine; D006801:Humans; D008706:Methemoglobin; D013053:Spectrophotometry
D006455:Hemoglobins, Abnormal; C027541:hemoglobin M Boston; D006639:Histidine; C028907:hemoglobin Saskatoon; D008706:Methemoglobin; C027542:hemoglobin M Iwate; C027543:hemoglobin M Milwaukee; D006449:Hemoglobin M