title: Hemoglobin Saint Mandé [beta 102 (G4) Asn----Tyr]. Functional studies and structural modeling reveal an altered T state.
abstract: Oxygen equilibrium studies of purified hemoglobin Saint Mandé (Hb SM) [beta 102 (G4) Asn----Tyr] reveal a decreased oxygen affinity and cooperativity but to a lesser extent than found for Hb Kansas (beta 102 Thr). The low affinity of Hb SM depends on environmental conditions: eliminating chloride or raising the pH greatly elevated the ratio of p50 of Hb SM to that of Hb A. The alkaline Bohr effect is reduced by about 40%. The effects of anions (chloride, organophosphates) binding to deoxy Hb SM are also reduced. These data indicate that the functional properties of Hb SM are intermediary between Hb A and Hb Kansas. In addition, molecular graphics modeling of Hb SM in the oxy and deoxy structures indicate the possibility of a new hydrogen bond in the T state between beta(1)102 Tyr and alpha(2)42 Tyr. Stabilisation of the T state in this manner is a plausible explanation for several of the effects observed.
authors: Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Paris-Sud, France.
authors: C
authors: C
authors: Poyart
authors: O
authors: O
authors: Schaad
authors: J
authors: J
authors: Kister
authors: F
authors: F
authors: Galacteros
authors: S J
authors: SJ
authors: Edelstein
authors: Y
authors: Y
authors: Blouquit
authors: N
authors: N
authors: Arous
mesh_terms: D001216:Asparagine / Q000235:genetics; D006455:Hemoglobins, Abnormal / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D014443:Tyrosine / Q000235:genetics
chemical_list: D006455:Hemoglobins, Abnormal; D014443:Tyrosine; D001216:Asparagine; C030556:hemoglobin Saint Mande; D010100:Oxygen