title: Functional alterations in adult and fetal hemoglobin Sassari Asp-alpha 126(H9)-->His. The role of alpha 1 alpha 2 contact.
abstract: The effects of pH, organic phosphates (2,3-diphosphoglycerate), 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 (n50 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.
authors.affiliation: Institute of Biological Chemistry, University of Cagliari, Italy.
authors.forename: M T
authors.initials: MT
authors.lastname: Sanna
authors.forename: B
authors.initials: B
authors.lastname: Giardina
authors.forename: R
authors.initials: R
authors.lastname: Scatena
authors.forename: M
authors.initials: M
authors.lastname: Pellegrini
authors.forename: A
authors.initials: A
authors.lastname: Olianas
authors.forename: L
authors.initials: L
authors.lastname: Manca
authors.forename: B
authors.initials: B
authors.lastname: Masala
authors.forename: M
authors.initials: M
authors.lastname: Castagnola
authors.forename: M
authors.initials: M
authors.lastname: Corda
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001224:Aspartic Acid; D005260:Female; D005312:Fetal Blood; D005319:Fetal Hemoglobin / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D006580:Genetic Carrier Screening; D006441:Hemoglobin A / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D006455:Hemoglobins, Abnormal / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D006639:Histidine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D046911:Macromolecular Substances; D008297:Male; D008969:Molecular Sequence Data; D010108:Oxyhemoglobins / Q000378:metabolism; D017354:Point Mutation
chemical_list: D006455:Hemoglobins, Abnormal; D046911:Macromolecular Substances; D010108:Oxyhemoglobins; C053966:hemoglobin Sassari; D001224:Aspartic Acid; D006639:Histidine; D006441:Hemoglobin A; D005319:Fetal Hemoglobin