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Pu P, Lu S, Niu Z, Zhang T, Zhao Y, Yang X, Zhao Y, Tang X, Chen Q. Oxygenation properties and underlying molecular mechanisms of hemoglobins in plateau zokor ( Eospalax baileyi). Am J Physiol Regul Integr Comp Physiol 2019; 317:R696-R708. [PMID: 31508994 DOI: 10.1152/ajpregu.00335.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The plateau zokor (Eospalax baileyi) is a species of subterranean rodent endemic to the Tibetan Plateau. It is well adapted to the cold and hypoxic and hypercapnic burrow. To study the oxygenation properties of plateau zokor hemoglobins (Hbs), we measured intrinsic Hb-O2 affinities and their sensitivities to pH (Bohr effect); CO2; Cl-, 2,3-diphosphoglycerate (DPG); and temperature using purified Hbs from zokor and mouse. The optimal deoxyHb model of plateau zokor was constructed and used to study its structural characteristics by molecular dynamics simulations. O2 binding results revealed that plateau zokor Hbs exhibit remarkably high intrinsic Hb-O2 affinity, low CO2 effects compared with human and the relatively low anion allosteric effector sensitivities (DPG and Cl-) at normal temperature, which would safeguard the pulmonary Hb-O2 loading under hypoxic and hypercapnic conditions. Furthermore, the high anion allosteric effector sensitivities at low temperature and low temperature sensitivities of plateau zokor Hbs would facilitate the releasing of O2 in cold extremities and metabolic tissues. However, the high Hb-O2 affinity of plateau zokor is not compensated by high pH sensitivity as the Bohr factors of plateau zokor Hbs were as low as those of mouse. The results of molecular dynamics simulations revealed the reduced hydrogen bonding between the α1β1- and α2β2-dimer interface of deoxyHb in zokor compared with mouse. It may be the primary mechanism of the high intrinsic Hb-O2 affinities in zokor. Specifically, substitution of the 131Ser→Asn in the α2-chain weakened the connection between α1- and β2-subunit.
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Affiliation(s)
- Peng Pu
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Songsong Lu
- Faculty of Forestry, Gansu Agricultural University, Lanzhou, Gansu, China
| | - Zhiyi Niu
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Tao Zhang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Yaofeng Zhao
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Xingwen Yang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Yao Zhao
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Xiaolong Tang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Qiang Chen
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, Gansu, China
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Weber RE, Jarvis JUM, Fago A, Bennett NC. O 2 binding and CO 2 sensitivity in haemoglobins of subterranean African mole rats. ACTA ACUST UNITED AC 2017; 220:3939-3948. [PMID: 28851819 DOI: 10.1242/jeb.160457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 08/23/2017] [Indexed: 01/05/2023]
Abstract
Inhabiting deep and sealed subterranean burrows, mole rats exhibit a remarkable suite of specializations, including eusociality (living in colonies with single breeding queens), extraordinary longevity, cancer immunity and poikilothermy, and extreme tolerance of hypoxia and hypercapnia. With little information available on adjustments in haemoglobin (Hb) function that may mitigate the impact of exogenous and endogenous constraints on the uptake and internal transport of O2, we measured haematological characteristics, as well as Hb-O2 binding affinity and sensitivity to pH (Bohr effect), CO2, temperature and 2,3-diphosphoglycerate (DPG, the major allosteric modulator of Hb-O2 affinity in red blood cells) in four social and two solitary species of African mole rats (family Bathyergidae) originating from different biomes and soil types across Central and Southern Africa. We found no consistent patterns in haematocrit (Hct) and blood and red cell DPG and Hb concentrations or in intrinsic Hb-O2 affinity and its sensitivity to pH and DPG that correlate with burrowing, sociality and soil type. However, the results reveal low specific (pH independent) effects of CO2 on Hb-O2 affinity compared with humans that predictably safeguard pulmonary loading under hypoxic and hypercapnic burrow conditions. The O2 binding characteristics are discussed in relation to available information on the primary structure of Hbs from adult and developmental stages of mammals subjected to hypoxia and hypercapnia and the molecular mechanisms underlying functional variation in rodent Hbs.
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Affiliation(s)
- Roy E Weber
- Department of Bioscience, Aarhus University, C.F. Møllers Alle 3, Aarhus C 8000, Denmark
| | | | - Angela Fago
- Department of Bioscience, Aarhus University, C.F. Møllers Alle 3, Aarhus C 8000, Denmark
| | - Nigel C Bennett
- Zoology and Entomology Department, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
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Storz JF. Gene Duplication and Evolutionary Innovations in Hemoglobin-Oxygen Transport. Physiology (Bethesda) 2017; 31:223-32. [PMID: 27053736 DOI: 10.1152/physiol.00060.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During vertebrate evolution, duplicated hemoglobin (Hb) genes diverged with respect to functional properties as well as the developmental timing of expression. For example, the subfamilies of genes that encode the different subunit chains of Hb are ontogenetically regulated such that functionally distinct Hb isoforms are expressed during different developmental stages. In some vertebrate taxa, functional differentiation between co-expressed Hb isoforms may also contribute to physiologically important divisions of labor.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
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Singer GA, Kleinschmidt T, Pettigrew JD, Braunitzer G. The primary structure of the hemoglobin from the tomb bat (Taphozous georgianus, Microchiroptera). BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1992; 373:937-42. [PMID: 1466792 DOI: 10.1515/bchm3.1992.373.2.937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The primary structures of the alpha- and beta-chains of the single hemoglobin component from the tomb bat (Taphozous georgianus, Microchiroptera) are presented. After chain separation by reversed-phase HPLC the sequences could be determined by automatic gas and liquid phase Edman degradation of the chains and their tryptic peptides. The alpha- and beta-chains differ from human hemoglobin by 14 and 18 replacements, respectively. Compared to the total number of amino-acid exchanges, the exchange rate in the interhelical regions of the alpha-chains is surprisingly high (25%). It seems unlikely that substitutions at contact positions affect the oxygen binding properties of the hemoglobin.
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Affiliation(s)
- G A Singer
- Max-Planck-Institut für Biochemie, Abteilung Proteinchemie, Martinsried bei München
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Condò SG, el-Sherbini S, Shehata YM, Corda M, Pellegrini MG, Brix O, Giardina B. Hemoglobins from bats (Myotis myotis and Rousettus aegyptiacus): a possible example of molecular adaptation to different physiological requirements. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1989; 370:861-7. [PMID: 2590470 DOI: 10.1515/bchm3.1989.370.2.861] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The functional properties of the hemoglobin systems from two different species of bat i.e. Rousettus aegyptiacus and Myotis myotis have been studied as a function of chloride, polyphosphates, pH and temperature. Apart from overall similarities shared with most mammalian hemoglobins, the two systems show significant differences with respect to the effect of chloride and temperature sensitivity. These findings have been related to the different physiological needs of the two species.
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Affiliation(s)
- S G Condò
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Italy
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Kleinschmidt T, Rücknagel KP, Weber RE, Koop BF, Braunitzer G. Primary structure and functional properties of the hemoglobin from the free-tailed bat Tadarida brasiliensis (Chiroptera). Small effect of carbon dioxide on oxygen affinity. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1987; 368:681-90. [PMID: 3113446 DOI: 10.1515/bchm3.1987.368.1.681] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hemoglobin of the Free-Tailed Bat Tadarida brasiliensis (Microchiroptera) comprises two components (Hb I and Hb II) in nearly equal amounts. Both hemoglobins have identical beta-chains, whereas the alpha-chains differ in having glycine (Hb I) or aspartic acid (Hb II) in position 115 (GH3). The components could be isolated by DEAE-Sephacel chromatography and separated into the globin chains by chromatography on carboxymethyl-cellulose CM-52. The sequences have been determined by Edman degradation with the film technique or the gas phase method (the alpha I-chains with the latter method only), using the native chains and tryptic peptides, as well as the C-terminal prolyl-peptide obtained by acid hydrolysis of the Asp-Pro bond in the beta-chains. The comparison with human hemoglobin showed 18 substitutions in the alpha-chains and 24 in the beta-chains. In the alpha-chains one amino-acid exchange involves an alpha 1/beta 1-contact. In the beta-chains one heme contact, three alpha 1/beta 1- and one alpha 1/beta 2-contacts are substituted. A comparison with other chiropteran hemoglobin sequences shows similar distances to Micro- and Megachiroptera. The oxygenation characteristics of the composite hemolysate and the two components, measured in relation to pH, Cl-, and 2,3-bis-phosphoglycerate, are described. The effect of carbon dioxide on oxygen affinity is considerably smaller than that observed in human hemoglobin, which might be an adaptation to life under hypercapnic conditions.
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