Physical and chemical properties of opossum hemoglobin. A hemoglobin containing glutamine at position 58 (E7) in the alpha subunit (original) (raw)
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Hemoglobins Austin and Waco: Two Hemoglobins with substitutions in the α1β2 contact region
Archives of Biochemistry and Biophysics, 1977
Hemoglobins (Hbs) Austin and Waco were detected by their electrophoretic migration on cellulose acetate (pH 8.4) and citrate agar (pH 6.2). By these methods, both variants migrated between Hbs A and F. Globin chain analysis at pH 8.6 indicated that the mutant 6 chain of Hb Austin was faster moving than the 6" chain; however, the mutant chain of Hb Waco was indistinguishable from the PA chain by this technique. The two variants were isolated by ion-exchange column chromatography. Sequence studies demonstrated a substitution of serine (Hb Austin) and lysine (Hb Waco) for arginine at position 40 in the /3 chain. These mutations involve an amino acid residue in the a& contact region, which, before this report, had been considered invariant in all hemoglobin sequences. Hb Austin was found to exist as dimers when oxygenated and as tetramers when deoxygenated. The equilibrium constant (K,) for the tetramer to dimer transition was approximately 300 x 10e6 M, as calculated from sedimentation velocity studies. This variant also had high oxygen affinity, a much reduced heme-heme interaction, and a normal Bohr effect. The functional properties of Hb Waco were similar to those of Hb A.
Biological Chemistry Hoppe-Seyler, 1989
The blood of the adult swift contains one major (HbA = ^ 2) and two minor components (HbD = «2^2 and HbD'). The components were separated by FPLC with a TSK SP-5 PW-column in phosphate buffers, and were eluted with a linear NaCl gradient. HbD' could be detected only in freshly prepared hemolysates with the sensitive FPLC separation method.The globin chains were separated on a cation exchanger (CM-cellulose), the tryptic peptides by HPLC with a RP-2 LiChrosorb column. Their amino-acid sequences were determined by automatic Edman degradation with the film-or gas-phase method. For the a A-, a D-and ß-chains, peptide alignment was achieved by homologous comparison with the corresponding chains of the greylag goose (Anser anser). The structural significance of the substitutions was examined with the aid of molecular graphics. The oxygen-binding properties of the stripped hemolysate and of HbA and HbD and their dependence on pH, temperature and inositol polyphosphate are presented and discussed with reference to molecular structures and hypothermy that occurs during torpidity. Die Hämoglobine des adulten Mauerseglers (Apus apus, Apodiformes) und ihre physiologischen Eigenschaften. Die Sequenz der Haupt-(HbA) und Nebenkomponente (HbD) * 149th communication on hemoglobins; for 148th communication see ref.^.
Characterization of hemoglobin bassett (α94Asp→Ala), a variant with very low oxygen affinity
American Journal of Hematology, 2004
Hemoglobin (Hb) Bassett, an abnormal Hb variant with a markedly reduced oxygen affinity, was discovered in a Caucasian (Anglo‐Saxon) male child who experienced episodes of cyanosis. Cation‐exchange and reversed‐phase (RP) high‐performance liquid chromatography (HPLC) showed that the patient has an abnormal Hb, with a mutation in the α‐globin. Tryptic peptide digest of the abnormal α‐globin with subsequent HPLC analysis revealed abnormal elution of the α‐T11 peptide. Further studies with Edman sequencing and electrospray mass spectrometry of tryptic peptide α‐T11, as well as structural analysis by X‐ray crystallography revealed an Asp→Ala substitution at the α94 (G1) position, a match for Hb Bassett. Detailed functional studies showed that this Hb variant had a markedly reduced oxygen affinity (P50 at pH 7.0 = 22 mmHg; Hb A P50 = 10.5 mmHg), reduced Bohr effect (−0.26 compared to − 0.54 in Hb A), and low subunit cooperativity (n = 1.4, compared to 2.6 in Hb A). X‐ray crystallography ...
The presence of two major hemoglobin components in an inbred strain of mice
Proceedings of the National Academy of Sciences, 1966
For a number of reasons, laboratory mice offer an excellent system for the study of genetic control of hemoglobin structure. Mice have a rapid generation time, and therefore, large populations inbred for generations are readily available. Previous investigations have shown that the hemoglobins of different strains of mice are not identical when investigated by paper electrophoresis,l column chromatography,2 and "fingerprinting," following tryptic digestion of the separated a and c chains.2' 3
Journal of Biological Chemistry, 1999
The ferric form of the homodimeric Scapharca hemoglobin undergoes a pH-dependent spin transition of the heme iron. The transition can also be modulated by the presence of salt. From our earlier studies it was shown that three distinct species are populated in the pH range 6 -9. At acidic pH, a low-spin six-coordinate structure predominates. At neutral and at alkaline pHs, in addition to a small population of a hexacoordinate high-spin species, a pentacoordinate species is significantly populated. Isotope difference spectra clearly show that the heme group in the latter species has a hydroxide ligand and thereby is not coordinated by the proximal histidine. The stretching frequency of the Fe-OH moiety is 578 cm ؊1 and shifts to 553 cm ؊1 in H 2 18 O, as would be expected for a Fe-OH unit. On the other hand, the ferrous form of the protein shows substantial stability over a wide pH range. These observations suggest that Scapharca hemoglobin has a unique heme structure that undergoes substantial redox-dependent rearrangements that stabilize the Fe-proximal histidine bond in the functional deoxy form of the protein but not in the ferric form.
Structure/Function Relationships in the Hemoglobin Components from Moray (Muraena Helena
European Journal of Biochemistry, 1995
Concerning thc number and type of the hemoglobin componcnts, the morny M u r u~i t i~ heleiia is characterized by three diffcrcnt phenotypes whose frequencies arc ncarly identical. Thus, the cathodal cornponent is present in all individuals, whereas one or both of two anodal components may be present in the same phenotype. These components have been separated by chromatography.