Tertiary structure variability within the quaternary states of hemoglobin: a spin label study

Johnson, Michael E.; Scholler, Diane M.; Hoffman, Brian M.; Ho, Chien

doi:10.1016/0005-2795(78)90085-5

Cited by 3 publications

(1 citation statement)

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“…The interpretation of kinetic association/dissociation measurements on des(His HC3,B) and des(His HC3f, Tyr HC2f) lead to the conclusion that the H-bond between Tyr HC3f and Val FG53 is an important pathway of the tertiary structure variations induced by proton binding in the following sense: the protonation of surface histidines (pK -6.6) (e.g., His HC3f) influences the equilibrium between two conformational states of the Tyr HC3,B aromatic ring (Shaanan, 1983;Johnson et al, 1978). This structural change is transduced to the heme via the H-bond between Tyr HC2f and Val Fg5o and the central and peripheral contacts between the heme and the F-, FGhelices of the protein.…”

Section: Introductionmentioning

confidence: 99%

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Schweitzer‐Stenner¹,

Wedekind²,

Dreybrodt³

1986

Biophysical Journal

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The dispersion of the depolarization ratio of oxidation and spinmarker lines of oxyhemoglobin at low C1- concentration (less than 0.08 M) have been examined for different pH values in the acid and alkaline region. Interpreting the depolarization ratio dispersion curves by fifth order Loudon theory of the polarizibility tensor, we obtain tensor parameters depending linearly on symmetry classified distortions of the functional hemegroup. The pH dependence of these parameters are explained by assuming the influence of three titrable groups with pK = 7.8, 6.6, and 5.8 on the heme. Using these pK values, we are able to interpret the pH dependence of CO(O2)-dissociation and CO-association of the fourth hemoglobin subunit. We conclude from our measurements that the change of the Tyr HC2 beta-configuration induces heme-apoprotein interaction via the Tyr HC2 beta-Val FG5 beta H-bond, which are transduced to the heme via central and peripheral coupling.

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Section: Introductionmentioning

confidence: 99%

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Schweitzer‐Stenner¹,

Wedekind²,

Dreybrodt³

1986

Biophysical Journal

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Equilibrium Aspects of the Binding of myo‐Inositol Hexakisphosphate to Human Hemoglobin as Studied by ³¹P NMR and pH‐Stat Techniques

Zuiderweg¹,

Hamers

Bruin

et al. 1981

European Journal of Biochemistry

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The interaction of myo-inositol hexakisphosphate (P,-inositol) with human hemoglobin has been studied as a function of pH using pH-stat techniques and 31P NMR. With the pH-stat method the following data were obtained: the association constants for the P,-inositolldeoxyhemoglobin and P,-inositol/carboxyhemoglobin complexes at alkaline and acid pH respectively and the proton absorption curves associated with the protein/phosphate interaction for both complexes from pH 5.5 to pH 9. From these data the affinities of P,-inositol towards deoxyhemoglobin (Hb) and carboxyhemoglobin (HbCO) have been calculated as a function of pH. The shape of the proton absorption curves was found to be strongly dependent on the ligation state of the hemoglobin molecule.The pH dependence of the 31P N M R spectra of P,-inositol bound to Hb or HbCO provides a monitor for the proton-binding behaviour of the phosphate groups of P,-inositol when present in the central cavity of the protein. It appears that this behaviour is only slightly dependent on the ligation state of the hemoglobin molecule. The NMR spectral data were interpreted in terms of a model which takes into account the electrostatic interaction between the phosphate groups within the P,-inositol molecule as well as the electrostatic interaction between the phosphate groups and positively charged groups on the protein.To account for the discrepancy between the pH-stat and 31P N M R results, i.e. a strong dependence of the protonabsorption curves and a weak dependence of the proton-binding behaviour of P,-inositol on the ligation state of the protein respectively, it is proposed that a conformational change takes place in HbCO upon P,-inositol binding. Arnone and Perutz [S] showed that in deoxyhemoglobin P,-inositol binds to a cluster of eight positively charged residues located at the 8-chain side of the central cavity. Their analysis was confirmed by studies on the binding of P,-inositol to mutant hemoglobins. It was shown that the strength of binding depends on replacements of these residues [9-1 I]. At moderate ionic strength P,-inositol forms a tight 1 : 1 complex with deoxyhemoglobin. The association constant was found to be 1.6 x IO'M-l at pH7.3 in 0.1 M NaCl [12].Recent experiments showed that the binding site for polyphosphate molecules in ligated hemoglobin is also located at the entrance of the central cavity [I 3 -151. The stoichiometry of binding was found to be unity [13]. From oxygenation experiments [I 61 the affinity of P,-inositol towards ligated hemoglobin is known to be low at neutral pH.The proton-binding behaviour of P,-inositol free in solution was studied in detail in a previous paper [17]. It was shown that P,-inositol bears a 12-fold negative charge above pH 11 while all phosphate groups display an anomalous proton-binding behaviour below that pH. As was demonAbbreviations. P,-inositol, nzyo-inositol 1,2,3,4,5,6-hexisphosphate; Hb, deoxyhemoglobin; HbCO, carboxyhemoglobin; 3 1 P NMK, phosphorus nuclear magnetic resonance spectroscopy. strated, this anom...

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Spectral, Conformational and Chemical Properties of Opossum Methemoglobin

John

Waterman

2005

European Journal of Biochemistry

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Opossum methemoglobin differs from methemoglobin A in spectral, spin state, conformational and chemical properties. The primary structural alterations in opossum hemoglobin, including the critical substitution at a58 (E7) His ---f Gln result in the following properties. (a) Major contribution of the spectral transitions due to inositol hexakisphosphate binding arises from the x chains. (b) The aquomet to hydroxymet (high-spin to low-spin) transition as a function of pH is slightly retarded resulting in considerable high spin at alkaline pH. (c) The tertiary conformation (t) around the / 3 hemes, upon transition to a T quaternary state, differs from the known hemoglobin t tertiary structure. (d) Both a and ,9 hemes are susceptible to rapid reduction by ascorbic acid (the reduction rate being tenfold faster than that of methemoglobin A). These properties suggest that the heme environments in both the a and subunits of opossum hemoglobin are different from those of human hemoglobin A.The complete amino acid sequence of the a and /j chains of opossum (Didelphius marsupialis) hemoglobin reveals 83 residue differences when compared to human hemoglobin A TI]. The a-chain heme environment of opossum hemoglobin is modified due to the presence of glutamine in place of the distal histidine at position a58 (E7) and also by the presence of a methionine residue at a25 (B6), which by virtue of its larger size compared with the glycine residue in hemoglobin A can alter the stability and rigidity of B and

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Tertiary structure variability within the quaternary states of hemoglobin: a spin label study

Cited by 3 publications

References 30 publications

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Equilibrium Aspects of the Binding of myo‐Inositol Hexakisphosphate to Human Hemoglobin as Studied by ³¹P NMR and pH‐Stat Techniques

Spectral, Conformational and Chemical Properties of Opossum Methemoglobin

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Tertiary structure variability within the quaternary states of hemoglobin: a spin label study

Cited by 3 publications

References 30 publications

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Correspondence of the pK values of oxyHb-titration states detected by resonance Raman scattering to kinetic data of ligand dissociation and association

Equilibrium Aspects of the Binding of myo‐Inositol Hexakisphosphate to Human Hemoglobin as Studied by 31P NMR and pH‐Stat Techniques

Spectral, Conformational and Chemical Properties of Opossum Methemoglobin

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Equilibrium Aspects of the Binding of myo‐Inositol Hexakisphosphate to Human Hemoglobin as Studied by ³¹P NMR and pH‐Stat Techniques