| Autor: |
CORDA, Marcella, DE ROSA, Maria C., PELLEGRINI, Maria G., SANNA, Maria T., OLIANAS, Alessandra, FAIS, Antonella, MANCA, Laura, MASALA, Bruno, ZAPPACOSTA, Bruno, FICARRA, Silvana, CASTAGNOLA, Massimo, GIARDINA, Bruno |
| Zdroj: |
Biochemical Journal; February 2000, Vol. 346 Issue: 1 p193-199, 7p |
| Abstrakt: |
Haemoglobin (Hb) J-Sardegna [α50(CE8)His → Asp] is a haemoglobin variant characteristic of subjects from the island of Sardinia. Here we report a study of the functional properties of both fetal and adult Hb J-Sardegna. The results indicate that adult Hb J-Sardegna displays an oxygen affinity that is higher than that of adult Hb only in the presence of 2,3-diphosphoglycerate (2,3-DPG). On the contrary, at 20 °C, the oxygen affinity of fetal Hb J-Sardegna is identical to that of normal fetal haemoglobin, both in the presence and in the absence of 2,3-DPG. A significant difference between these two systems (i.e. a higher oxygen affinity of fetal Hb J-Sardegna) shows up very clearly only when temperature is increased to 37 °C. Hence in fetal Hb, the main effect of the amino acid substitution is a decrease in the overall enthalpy change of oxygenation. The results outline the role of the α1-β1 interface in assessing the thermodynamics of oxygen binding. The functional properties of both adult and fetal Hb J-Sardegna have been interpreted at the structural level in light of the results obtained by a computational modelling approach performed in comparison with HbA and Hb Aichi, a variant characterized by a different mutation [α50(CE8)His → Arg] at the same position. |
| Databáze: |
Supplemental Index |
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