Hemoglobin Kariya [alpha 40 (C5) Lys leads to Glu]: a new hemoglobin variant with an increased oxygen affinity

A new abnormal hemoglobin, Hb Kariya [alpha 40 (C5) Lys leads to Glu], with an amino acid substitution at the alpha 1 beta 2 contact was discovered in a young Japanese man. This variant migrated to the anode faster than Hb A, being nearly the same as Hb I in electrophoretic mobility. It amounted to about 6% of the total hemoglobin of the hemolysate. This hemoglobin showed an increased oxygen affinity, decreased heme-heme interaction and a lowered 2,3-DPG effect.     

Hemoglobin Fort Gordon or alpha2beta2145 Tyr replaced by Asp, a new high-oxygen-affinity hemoglobin variant.

Hemoglobin Fort Gordon, alpha2beta2145 Tyr replaced by Asp (HC2), has been observed in a 20-year-old black male with compensatory erythrocytosis. The variant was readily identified by electrophoresis and chromatography, and comprised about 30% of the red cell hemoglobin. The substitution was identified through analyses of tryptic peptides of various digests of the isolated beta chain. The oxygen affinity of whole blood was increased; two components were observed one of which had a greatly increased affinity for oxygen and a markedly reduced subunit cooperativity. It appears that the Tyr replaced by Asp substitution resembles the Tyr replaced by His substitution in hemoglobin Bethesda (Bunn, H. F. et al. (1972) J. Clin. Invest. 51, 2299-2309; Olson, J. S. and Gibson, G. H. (1972) J Biol. Chem. 247, 3662-3670; Adamson et al. (1972) J. Clin. Invest. 51, 2883-2888) in that both inhibit the quarternary change of the oxy to the deoxy conformation, resulting in greatly altered functional properties. Studies of a few members of the family were negative.     

Hemoglobin Roseau-Pointe a Pitre alpha 2 beta 2(90) (F6) Glu----Gly: a new hemoglobin variant with slight instability and low oxygen affinity

A Dominican neonate carrying a new abnormal hemoglobin, hemoglobin Roseau Pointe-à-Pitre alpha 2 beta 2(90)(F6) Glu----Gly, was detected in Guadeloupe during application of a cord blood screening program. This variant behaved in isoelectrofocusing as an Hb D, and displayed instability and low whole blood oxygen affinity. In the affected family it was present, either isolated, or in association with a beta+ thalassemia trait.     

Hemoglobin Fannin-Lubbock [alpha2 beta 2 119 (GH2) Gly replaced by Asp]. A new hemoglobin variant at the alpha1 beta 1 contact.

Hemoglobin Fannin-Lubbock was found in a 9-year-old Mexican-American female. The abnormal hemoglobin was detected as a fast-moving variant by electrophoresis on cellulose acetate at pH 8.4. Structural analysis indicated a substitution in the beta-chain of aspartic acid for glycine at position 119, a position involved in the alpha1beta1 contact of the hemoglobin tetramer. This contact between unlike chains is larger and undergoes a smaller shift during the process of oxygenation and deoxygenation that the alpha1beta2 contact (Perutz, M.F., Muirhead, H., Cox, J.M. and Goaman, L.C.G. (1968) Nature 219, 131-139). Mutations in this contact tend to cause slight or no changes in functional behavior. Apart from a mild anemia, the propositus did not exhibit any obvious clinical symptoms.     

Hemoglobin-Strumica or alpha 2 112(G19) His replaced by Arg beta 2. (With an addendum: hemoglobin-J-Paris-I, alpha 2 12(A10) Ala replaced by Asp beta 2, in the same population).

Hemoglobin-Strumica has been observed in five members of a Macedonian family. Histidyl residue in position 112 of the alpha chain of this variant is replaced by an arginyl residue. Two other variants (hemoglobin-Dakar and hemoglobin-Hopkins-2) in which this histidyl residue has been replaced by a glutaminyl and by an aspartyl residue, respectively, have been described (Rosa et al. (1968) 12 thCongr. Int. Soc. Haematol. New York, abstract, p. 73 and Charache, S. and Osterag, W. (1970) Bloodt 36, 852). The hemoglobin-Strumica heterozygotes have minimal hematological changes although this may not necessarily be associated with the hemoglobinopathy. Subjects heterozygous for hemoglobin-Dakar have a mild hemolytic anemia and hemoglobin-Hopkins-2 heterozygotes exhibit minimal hematological changes.     

Identification of hemoglobin G-Philadelphia (alpha 68 Asn replaced by Lys) and hemoglobin Matsue-Oki (alpha 75 Asp replaced by Asn) in a black infant

Two alpha-chain variants, Hb G-Philadelphia and Hb Matsue-Oki, were present in members of a relatively large black family from South Carolina. The four Hb G-Philadelphia heterozygotes averaged 35.6% Hb G, suggesting the presence of an alpha-thalassemia-2 condition in cis to the Hb G mutation, which was confirmed by DNA structural analysis. The seven Hb Matsue-Oki heterozygotes averaged 22.2% Hb MO and likely have four active alpha-chain genes. One infant was a compound heterozygote for the two Hb variants which could not be separated from each other. The quantity of Hb G plus Hb MO was 58% by DEAE-cellulose chromatography and 69% by chain analyses. These results and the family data indicate that this child had three active alpha-chain genes, of which one regulated the synthesis of the normal alpha chain, one was mutated to give the alpha G chain, and one to give the alpha MO chain. The amino acid substitutions in Hb G-Philadelphia and Hb Matsue-Oki are located in the tryptic peptide alpha T-9, which is 29 amino acid residues long. Structural analyses of these abnormalities made use of high-pressure liquid chromatography for the separation of both tryptic and thermolytic peptides and of a highly sensitive ultra-micro sequencing procedure. Although the alpha 68 Asn replaced by Lys substitution is readily demonstrable in Hb G-Philadelphia the elucidation of the alpha 75 Asp replaced by Asn replacement in Hb Matsue-Oki was greatly facilitated by the use of these microprocedures.     

A new hemoglobin variant. HB Yatsushiro alpha 2 A beta 2 60 Val replaced by Leu

This study was performed to establish the structural abnormality of a new hemoglobin variant discover-d in a Japanese patient with angina pectoris. The hybridization of the separated hemoglobin with canine hemoglobin revealed a beta-chain anomaly. Peptide betaTp-6 was found to be abnormally located on the peptide map of tryptic digests of the S-carboxymethylated beta-chain from the variant hemoglobin. A structural study on the abnormal betaTp-6 revealed that the variant hemoglobin differs from hemoglobin A by substitution of leucine for valine at residue 60 of the beta-chain. This new variant hemoglobin is designated as hemoglobin Yatsushiro after the name of the city where the propositus lived. The patient is hematologically healthy and his clinical history has nothing to do with this abnormal hemoglobin.     

Structure of deoxy hemoglobin C (beta six Glu replaced by Lys) in two crystal forms

Five crystal forms of the abnormal human hemoglobin Hb³ C (beta six Glu → Lys) have been grown. Two of them are grown with liganded Hb C, three with deoxy Hb C. The structures of two of the deoxy crystal forms were determined by the method of molecular replacement, using deoxy Hb A as the model structure. Fourier maps were calculated for each Hb C structure, using data to a resolution of 5 Å in one case and 4 Å in the second case. The structural differences between each deoxy Hb C structure and the deoxy Hb A model are found mostly at the molecular surface. Energetically favorable interactions involving the variant residue, beta six lysine, occur in both Hb C crystal forms, and could explain the lowered solubility and enhanced tendency of deoxy Hb C to crystallize in vivo.     

Hemoglobin Tilburg: alpha 2-beta 2 73 (E 17) Asp----Gly. A new hemoglobin with reduced oxygen affinity

A new hemoglobin variant has been found in a Dutch Caucasian girl and detected also in members of three generations of her family. This variant is characterized by the substitution of an aspartic acid at position 73 (E 17) of the beta-chain with a glycine residue. Hemoglobin Tilburg makes up to 42% of the total hemoglobin in the blood of the proposita, it is stable at the isopropanol test, and not associated with significant hematological abnormalities in heterozygous carriers. The oxygen dissociation curve of the purified variant, carried out at different pH values, shows a definite reduction of the affinity for oxygen and a normal alkaline Bohr effect. Three more hemoglobins with a single amino acid substitution at the same site have been previously described: Hb Korle-Bu (Asp----Asn), Hb Mobile (Asp----Val) and Hb Vancouver (Asp----Tyr). In all these proteins the affinity for oxygen is lowered to an extent which is variable and characteristic of each mutant. In this paper we discuss the possible mechanism responsible for the abnormal behaviour of hemoglobins substituted at beta 73.     

Increased oxygen affinity for hemoglobin Sawara: alphaA4(6) aspartic acid replaced by alanine.

The oxygen binding property of Hb Sawara (alphaA4 Asp replaced by Ala) was studied at different pH values with and without addition of 2,3-diphosphoglycerate. The oxygen affinity of Hb Sawara was shown to be increased, the difference of the log P50 value between normal and abnormal hemoglobins being 0.37 at pH 7.0. Both the magnitude of the alkaline Bohr effect and the effect of 2,3-diphosphoglycerate upon oxygen affinity of Hb Sawara were comparable to those of Hb A. The amino acid substitution of alanine for alphaA4 aspartic acid might result in the loss of a stabilizing force for ionic interaction between the alpha-amino group of NA (1)alpha1 valine and the alpha-carboxyl of HC3(141)alpha2 arginine in the deoxy-form.     

Properties of hemoglobin G. Ferrara (beta57(E1) Asn replaced by Lys).

Hemoglobin G. Ferrara is an abnormal human hemoglobin in which an asparagine residue is replaced by a lysyl residue at position beta57 (beta57 Asn replaced by Lys). Oxygen equilibria show that cooperativity and alkaline Bohr effect are maintained to normal levels while the acid Bohr effect appears increased; in addition, a smaller effect of diphosphoglycerate is also observed. Flash photolysis experiments performed as a function of protein concentration show that the fraction of quickly reacting form is always higher than that of human hemoglobin A. This fact, together with the increase of the oxygen affinity observed at acid pH values, may be related to an enhanced dissociation of the molecule into dimers. Several attempts to isolate the native chains by treatment of the protein with p-chloromercuribenzoate were unsuccessful due to the great instability of the isolated variant beta-chains, which precipitated completely during incubation with p-chloromercuribenzoate. Therefore, although the substitution is on the surface of the molecule, there are several properties of hemoglobin G. beta Ferrara which are clearly different from hemoglobin A.     

Clinicohematologic effects of hemoglobin Altdorf (alpha 2 beta 2 135 Ala replaced by Pro)

Hb Altdorf alpha 2 beta 2 135 Ala leads to Pro is an unstable variant occurring near Lecce in Italy. The abnormal hemoglobin does not separate from Hb A in the electrophoresis. In vitro a marked Heinz body formation is produced with phenylhydrazin. In heterozygous individuals an almost compensated hemolysis and a slight splenomegaly are found. Hemolysis can be aggravated by exogenous factors. A rather severe hemolysis was induced by a viral infection in a 3 years old girl.