A Novel Allosteric Mechanism in Haemoglobin

Perutz, M. F.; Fermi, G.; Poyart, Claire; Pagnier, J.; Kister, J.

doi:10.1006/jmbi.1993.1530

Cited by 152 publications

(117 citation statements)

References 0 publications

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…This interpretation agrees with the minor role of the β-subunit Nterminus in DPG binding (Richard et al, 1993) compared with the original model for DPG binding proposed by Arnone (1972). In addition to impairing DPG binding, the β2His→Phe substitution that exchanges a basic residue with an apolar one also contributes to the reduced intrinsic O 2 affinity typical of feline Hb isoforms by moving the β-chain N-termini towards the center of the Hb molecule, thereby stabilizing the T-state conformation (Perutz et al, 1993;Safo and Abraham, 2001) even when the heme is fully ligated, as found for domestic cat Hb (Balasubramanian et al, 2014). Similarly, the low O 2 affinity and DPG insensitivity of bovine Hb is also attributable to amino acid substitutions in the β-subunit N-termini (β1Val deleted and β2His→Met), which stabilize the low-affinity T state and prevent DPG access to the central cavity (Perutz et al, 1993;Safo and Abraham, 2001).…”

Section: Oxygenation Properties Of Big Cat Hbssupporting

confidence: 86%

“…In addition to impairing DPG binding, the β2His→Phe substitution that exchanges a basic residue with an apolar one also contributes to the reduced intrinsic O 2 affinity typical of feline Hb isoforms by moving the β-chain N-termini towards the center of the Hb molecule, thereby stabilizing the T-state conformation (Perutz et al, 1993;Safo and Abraham, 2001) even when the heme is fully ligated, as found for domestic cat Hb (Balasubramanian et al, 2014). Similarly, the low O 2 affinity and DPG insensitivity of bovine Hb is also attributable to amino acid substitutions in the β-subunit N-termini (β1Val deleted and β2His→Met), which stabilize the low-affinity T state and prevent DPG access to the central cavity (Perutz et al, 1993;Safo and Abraham, 2001). Although amino acid substitutions replacing the key β2His with uncharged residues may cause a high Hb-O 2 affinity as a result of weakened DPG binding in species adapted to high altitudes (Weber and Fago, 2004;Weber, 2007), we find the opposite functional effect of the same substitution (i.e.…”

Section: Oxygenation Properties Of Big Cat Hbsmentioning

confidence: 99%

See 1 more Smart Citation

Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Janečka

Nielsen

Andersen

et al. 2015

Journal of Experimental Biology

View full text Add to dashboard Cite

Genetically based modifications of hemoglobin (Hb) function that increase blood-O 2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O 2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood-O 2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation that may contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O 2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O 2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O 2 -transport pathway.

show abstract

Section: Oxygenation Properties Of Big Cat Hbssupporting

confidence: 86%

Section: Oxygenation Properties Of Big Cat Hbsmentioning

confidence: 99%

Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Janečka

Nielsen

Andersen

et al. 2015

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…Although the OEC rightshift induced by chloride in bovine hemoglobin has been confirmed by Perutz et al [26], the mechanism proposed to explain this effect is different from that suggested by Fronticelli [16]. They showed that chloride reduces the oxygen affinity of mammalian hemoglobin by acting as an allosteric effector, neutralizing the electrostatic repulsion in the cavity through the center of the molecule but without binding to any specific sites [1,25,26]. Increasing cardiac output, cardiac index, myocardial stroke work efficiency and improving ventilation-perfusion inequalities by a decrease in pulmonary arterial pressure and pulmonary vascular resistance, hypertonic saline solutions could also improve blood oxygen binding [3,4].…”

Section: Discussionmentioning

confidence: 94%

“…The oxygen equilibrium curve (OEC) right shift induced by chloride in bovine hemoglobin was confirmed by Perutz et al [25]. Because hemoglobin functions differently in an artificial solution than in bovine red blood cells, in a previous study, Gustin et al [20] recorded the whole blood OEC under standardized conditions with and without added chloride.…”

Section: Introductionmentioning

confidence: 87%

Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves

et al. 2002

View full text Add to dashboard Cite

-The study was carried out on healthy Friesian calves (n = 10) aged between 10 and 30 days. Hypochloremia and alkalosis were induced by intravenous administration of furosemide and isotonic sodium bicarbonate. The venous and arterial blood samples were collected repeatedly. 2,3-diphosphoglycerate (2,3-DPG), hemoglobin and plasmatic chloride concentrations were determined. The red blood cell chloride concentration was also calculated. pH, PCO 2 and PO 2 were measured in arterial and mixed venous blood. The oxygen equilibrium curve (OEC) was measured in standard conditions. The correspondence of the OEC to the arterial and mixed venous compartments was calculated, taking blood temperature, pH and PCO 2 values into account. The oxygen exchange fraction (OEF%), corresponding to the degree of blood desaturation between the arterial and mixed venous compartments and the amount of oxygen released at the tissue level by 100 mL of blood (OEF Vol%) were calculated from the arterial and mixed venous OEC, combined with PO 2 and hemoglobin concentration. Oxygen delivery (DO 2 ) was calculated using the arterial oxygen content, the cardiac output measured by thermodilution, and the body weight of the animal. The oxygen consumption (VO 2 ) was derived from the cardiac output, OEF Vol% and body weight values. Despite the plasma hypochloremia, the erythrocyte chloride concentration was not influenced by furosemide and sodium bicarbonate infusion. Due to the alkalosis-induced increase in the 2,3-DPG, the standard OEC was shifted to the right, allowing oxygen to dissociate from hemoglobin more rapidly. These changes opposed the increased affinity of hemoglobin for oxygen induced by alkalosis. Moreover, respiratory 697 Vet. Res. 33 (2002) acidosis, hemoconcentration, and the slight decrease in the partial oxygen pressure in mixed venous blood (Pvo 2 ) tended to improve the OEF Vol% and maintain the oxygen consumption in a physiological range while the cardiac output, and the oxygen delivery were significantly decreased. It may be concluded that, despite reduced oxygen delivery, oxygen consumption is maintained during experimentally induced hypochloremic alkalosis in healthy 10-30 day old calves.blood oxygen binding / oxygen equilibrium curve / oxygen consumption / hypochloremic alkalosis / calf Résumé -Mécanismes contrôlant la consommation en oxygène lors d'alcalose hypochlorémique induite expérimentalement chez le veau. Ces études ont été menées chez des veaux sains de type laitier, de race Frisonne (n = 10), âgés de 10 à 30 jours. L'hypochlorémie et l'alcalose ont été induites par l'administration intraveineuse de furosémide et de bicarbonate de sodium isotonique. Des échantil-lons sanguins ont été prélevés, de manière répétée, au niveau artériel et veineux. Les concentrations en 2,3-diphosphoglycérate (2,3-DPG), en hémoglobine et en chlore plasmatique ont été déterminées. Les concentrations intra-érythrocytaires en chlore ont également été calculées. Les valeurs de pH, PCO 2 et PO 2 ont été déterminées dans le sang ar...

show abstract

“…X-ray data from a single crystal were collected and processed as described by Perutz et al (1993). A total of 25,572 reflections were collected in the shell between 22.0 and 2.48 Å; these reduced with a merging R factor of 9.6% to 15,560 uniquely indexed reflections, or 76% of the unique reflections in the shell.…”

Section: Methodsmentioning

confidence: 99%

Probing the α1β2 Interface of Human Hemoglobin by Mutagenesis

Vallone

Bellelli

Miele

et al. 1996

Journal of Biological Chemistry

View full text Add to dashboard Cite

The allosteric transition of hemoglobin involves an extensive reorganization of the ␣ 1 ␤ 2 interface, in which two contact regions have been identified. This paper concerns the effect of two mutations located in the "switch" (␣C3 Thr 3 Trp) and the "flexible joint" (␤C3 Trp 3 Thr). We have expressed and characterized one double and two single mutants: Hb ␣T38W/␤W37T, Hb ␤W37T, and Hb ␣T38W, whose structure has been determined by crystallography.We present data on: (i) the interface structure in the two contact regions, (ii) oxygen and CO binding kinetics and cooperativity, (iii) dissociation rates of deoxy tetramers and association rates of deoxy dimers, and (iv) the effect of NaI on deoxy tetramer dissociation rate constant.All the mutants are tetrameric and T-state in the deoxygenated derivative. Reassociation of deoxygenated dimers is not modified by interface mutations. DeoxyHb ␣T38W dimerizes 30% slower than HbA; Hb ␤W37T and Hb ␣T38W/␤W37T dissociate much faster. We propose a binding site for I ؊ at the switch region. The single mutants bind O 2 cooperatively; the double one is almost non-cooperative, a feature confirmed by CO binding. The functional data, analyzed with the twostate model, indicate that these mutations reduce the value of the allosteric constant L 0 .The three-dimensional structure of liganded and deoxyhemoglobin (Baldwin and Chothia, 1979;Shaanan, 1983;Perutz et al., 1987) indicates that the allosteric transition can be described topographically as a change in the relative orientation of the two dimers identified as ␣ 1 ␤ 1 and ␣ 2 ␤ 2 , which rotate with respect to each other and slide along the ␣ 1 ␤ 2 and ␣ 2 ␤ 1 interfaces. Therefore, the amino acid residues that contribute to the ␣ 1 ␤ 2 (and ␣ 2 ␤ 1 ) interface (Fig. 1) play a major role in controlling the relative stability of the allosteric states and, as a consequence, cooperativity. This interface contains residues of helix C and the FG corner of both chains. In total 17 residues establish interactions across the ␣FG-␤C and the ␣C-␤FG contacts with a pseudo-symmetric arrangement (Fig.

show abstract

A Novel Allosteric Mechanism in Haemoglobin

Cited by 152 publications

References 0 publications

Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves

Probing the α1β2 Interface of Human Hemoglobin by Mutagenesis

Contact Info

Product

Resources

About