The effects of pH, organic phosphates (2,3-diphospho- glycerate), and temperature on the functional properties of both adult and fetal hemoglobin Sassari alpha (Asp-126 --> His) have been studied. The functional properties of the adult variant are characterized by the following: (i) an oxygen affinity higher than that of normal HbA in all the experimental conditions used; (ii) a dramatic reduction of homotropic interactions (n(50) very close to unity); and (iii) a significant decrease of the effect of 2,3-diphosphoglycerate, which is 35% lower than that observed on HbA. The fetal variant shows an increased oxygen affinity compared with normal HbF and an almost abolished heme-heme interaction. The molecular basis of these functional differences is discussed in terms of the possible role played by the substitution of alpha (Asp-26 --> His) on the stability of the R state of the molecule due to a decreased interaction at the level of alpha(1) alpha(2) contact.
Sanna, M., Giardina, B., Scatena, R., Pellegrini, M., Olianas, A., Manca, L., Masala, B., Castagnola, M., Corda, M., FUNCTIONAL ALTERATIONS IN ADULT AND FETAL HEMOGLOBIN SASSARI ASP-ALPHA-126(H9) -] HIS - THE ROLE OF ALPHA(1)ALPHA(2) CONTACT, <<THE JOURNAL OF BIOLOGICAL CHEMISTRY>>, 1994; 269 (28): 18338-18342 [http://hdl.handle.net/10807/23660]
FUNCTIONAL ALTERATIONS IN ADULT AND FETAL HEMOGLOBIN SASSARI ASP-ALPHA-126(H9) -] HIS - THE ROLE OF ALPHA(1)ALPHA(2) CONTACT
Giardina, Bruno;Scatena, Roberto;Castagnola, Massimo;
1994
Abstract
The effects of pH, organic phosphates (2,3-diphospho- glycerate), and temperature on the functional properties of both adult and fetal hemoglobin Sassari alpha (Asp-126 --> His) have been studied. The functional properties of the adult variant are characterized by the following: (i) an oxygen affinity higher than that of normal HbA in all the experimental conditions used; (ii) a dramatic reduction of homotropic interactions (n(50) very close to unity); and (iii) a significant decrease of the effect of 2,3-diphosphoglycerate, which is 35% lower than that observed on HbA. The fetal variant shows an increased oxygen affinity compared with normal HbF and an almost abolished heme-heme interaction. The molecular basis of these functional differences is discussed in terms of the possible role played by the substitution of alpha (Asp-26 --> His) on the stability of the R state of the molecule due to a decreased interaction at the level of alpha(1) alpha(2) contact.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.