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Pu P, Niu Z, Ma M, Tang X, Chen Q. Convergent High O 2 Affinity but Distinct ATP-Mediated Allosteric Regulation of Hemoglobins in Oviparous and Viviparous Eremias Lizards from the Qinghai-Tibet Plateau. Animals (Basel) 2024; 14:1440. [PMID: 38791658 PMCID: PMC11117339 DOI: 10.3390/ani14101440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
The functional adaptation and underlying molecular mechanisms of hemoglobins (Hbs) have primarily concentrated on mammals and birds, with few reports on reptiles. This study aimed to investigate the convergent and species-specific high-altitude adaptation mechanisms of Hbs in two Eremias lizards from the Qinghai-Tibet Plateau. The Hbs of high-altitude E. argus and E. multiocellata were characterized by significantly high overall and intrinsic Hb-O2 affinity compared to their low-altitude populations. Despite the similarly low Cl- sensitivities, the Hbs of high-altitude E. argus exhibited higher ATP sensitivity and ATP-dependent Bohr effects than that of E. multiocellata, which could facilitate O2 unloading in respiring tissues. Eremias lizards Hbs exhibited similarly low temperature sensitivities and relatively high Bohr effects at lower temperatures, which could help to stably deliver and release O2 to cold extremities at low temperatures. The oxygenation properties of Hbs in high-altitude populations might be attributed to varying ratios of β2/β1 globin and substitutions on the β2-type globin. Notably, the Asn12Ala in lowland E. argus could cause localized destabilization of the E-helix in the tetrameric Hb by elimination of hydrogen bonds, thereby resulting in its lowest O2 affinity. This study provides a valuable reference for the high-altitude adaptation mechanisms of hemoglobins in reptiles.
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Affiliation(s)
- Peng Pu
- School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China;
| | - Zhiyi Niu
- Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, No. 222 Tianshui South Road, Lanzhou 730000, China; (Z.N.); (M.M.); (X.T.)
| | - Ming Ma
- Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, No. 222 Tianshui South Road, Lanzhou 730000, China; (Z.N.); (M.M.); (X.T.)
| | - Xiaolong Tang
- Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, No. 222 Tianshui South Road, Lanzhou 730000, China; (Z.N.); (M.M.); (X.T.)
| | - Qiang Chen
- Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, No. 222 Tianshui South Road, Lanzhou 730000, China; (Z.N.); (M.M.); (X.T.)
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Li M, Li X, Wu Z, Zhang G, Wang N, Dou M, Liu S, Yang C, Meng G, Sun H, Hvilsom C, Xie G, Li Y, Li ZH, Wang W, Jiang Y, Heller R, Wang Y. Convergent molecular evolution of thermogenesis and circadian rhythm in Arctic ruminants. Proc Biol Sci 2023; 290:20230538. [PMID: 37253422 PMCID: PMC10229229 DOI: 10.1098/rspb.2023.0538] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 05/02/2023] [Indexed: 06/01/2023] Open
Abstract
The muskox and reindeer are the only ruminants that have evolved to survive in harsh Arctic environments. However, the genetic basis of this Arctic adaptation remains largely unclear. Here, we compared a de novo assembled muskox genome with reindeer and other ruminant genomes to identify convergent amino acid substitutions, rapidly evolving genes and positively selected genes among the two Arctic ruminants. We found these candidate genes were mainly involved in brown adipose tissue (BAT) thermogenesis and circadian rhythm. Furthermore, by integrating transcriptomic data from goat adipose tissues (white and brown), we demonstrated that muskox and reindeer may have evolved modulating mitochondrion, lipid metabolism and angiogenesis pathways to enhance BAT thermogenesis. In addition, results from co-immunoprecipitation experiments prove that convergent amino acid substitution of the angiogenesis-related gene hypoxia-inducible factor 2alpha (HIF2A), resulting in weakening of its interaction with prolyl hydroxylase domain-containing protein 2 (PHD2), may increase angiogenesis of BAT. Altogether, our work provides new insights into the molecular mechanisms involved in Arctic adaptation.
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Affiliation(s)
- Manman Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Xinmei Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Zhipei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Guanghui Zhang
- Key Laboratory of Animal Biotechnology, Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Nini Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Mingle Dou
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Shanlin Liu
- Department of Entomology, China Agricultural University, West Yuanmingyuan Road, Beijing 100193, People's Republic of China
| | - Chentao Yang
- BGI Shenzhen, Shenzhen 518083, People's Republic of China
| | - Guanliang Meng
- Centre of Taxonomy and Evolutionary Research, Zoological Research Museum Alexander Koenig, 53113 Bonn, Germany
| | - Hailu Sun
- BGI Shenzhen, Shenzhen 518083, People's Republic of China
| | | | - Guoxiang Xie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Yang Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Zhuo hui Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Wei Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Yu Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Rasmus Heller
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Yu Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, People's Republic of China
- Key Laboratory of Animal Biotechnology, Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, People's Republic of China
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Draft Genome Assembly of an Iconic Arctic Species: Muskox (Ovibos moschatus). Genes (Basel) 2022; 13:genes13050809. [PMID: 35627194 PMCID: PMC9140810 DOI: 10.3390/genes13050809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 02/01/2023] Open
Abstract
Muskoxen (Ovibos moschatus) are Arctic species within the Caprinae subfamily that are economically and culturally significant to northern Indigenous communities. Low genetic diversity from repeated genetic bottlenecks, coupled with the effects of Arctic warming (e.g., heat stress, changing forage, pathogen range expansions), present conservation concerns for this species. Reference genome assemblies enhance our ecological and evolutionary understanding of species (which in turn aid conservation efforts). Herein, we provide a full draft reference genome of muskox using Illumina Hiseq data and cross-species scaffolding. The final reference assembly yielded a genome of 2,621,890,883 bp in length, a scaffold N50 of ~13.2 million, and an annotation identifying ~19.3 k genes. The muskox genome assembly and annotation were then used to reconstruct a phylogenetic tree which estimated muskoxen diverged from other ungulate species~12 Mya. To gain insight into the demographic history of muskoxen we also performed pairwise sequentially Markovian coalescent (PSMC) that identified two population bottlenecks coinciding with major glaciation events contributing to the notoriously low genetic variation observed in muskoxen. Overall, this genome assembly provides a foundation for future population genomic studies, such as latitudinal analyses, to explore the capacity of muskoxen to adapt to rapidly changing environments.
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Pu P, Zhao Y, Niu Z, Cao W, Zhang T, He J, Wang J, Tang X, Chen Q. Comparison of hematological traits and oxygenation properties of hemoglobins from highland and lowland Asiatic toad (Bufo gargarizans). J Comp Physiol B 2021; 191:1019-1029. [PMID: 33876256 DOI: 10.1007/s00360-021-01368-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 03/13/2021] [Accepted: 04/07/2021] [Indexed: 01/09/2023]
Abstract
The Asiatic toad (Bufo gargarizans) belonging to the family of Bufonidae (Anura: Amphibia) is successfully residing on the Qinghai-Tibetan Plateau (QTP). To investigate whether the oxygen delivery undergoes adaptive adjustments to high-altitude environments in Asian toads inhabiting the QTP (Zoige County, 3446 m), choosing low-altitude populations (Chengdu City, 500 m) as control, we measured hematological traits, O2 affinities of whole blood, Hb-O2 affinities of purified Hbs, their sensitivities to temperature, and allosteric effectors (H+, Cl- and ATP). Our results showed that high-altitude Asiatic toads possessed significantly increased hemoglobin concentration, hematocrit, and red blood cell count, but significantly decreased erythrocyte volume compared with low-altitude toads. The whole blood and purified Hbs of high-altitude Asiatic toads both exhibited significantly higher O2 affinities compared with low-altitude toads. Substantially increased intrinsic Hb-O2 affinities of high-altitude Asiatic toads Hbs are likely to be the main reason for its elevated Hb-O2 affinities given the anionic cofactor sensitivities of high- and low-altitude toads were similar. The Hbs of high-altitude toads were also characterized by distinctly strong Bohr effects at the low temperature and low-temperature sensitivities. The adaptive adjustments of hematological traits could enhance the blood-O2 carrying capacity of high-altitude Asiatic toads. The increased Hb-O2 affinities could safeguard the pulmonary O2 uploading under hypoxia. The strong Bohr effects at the low temperature could help the release of O2 in metabolic tissues and cold limbs, while low-temperature sensitivity could minimize the effect of temperature fluctuation on the Hb-O2 affinity.
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Affiliation(s)
- Peng Pu
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Yao Zhao
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Zhiyi Niu
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Wangjie Cao
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Tao Zhang
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Jie He
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Jinzhou Wang
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Xiaolong Tang
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China
| | - Qiang Chen
- Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, 730000, Gansu, China.
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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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Ribeiro D, Planchon S, Leclercq C, Raundrup K, Alves S, Bessa R, Renaut J, Almeida A. The muscular, hepatic and adipose tissues proteomes in muskox (Ovibos moschatus): Differences between males and females. J Proteomics 2019; 208:103480. [DOI: 10.1016/j.jprot.2019.103480] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/28/2019] [Accepted: 08/02/2019] [Indexed: 02/07/2023]
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Blix AS. Adaptations to polar life in mammals and birds. ACTA ACUST UNITED AC 2017; 219:1093-105. [PMID: 27103673 DOI: 10.1242/jeb.120477] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 01/25/2016] [Indexed: 12/22/2022]
Abstract
This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation. Newborn altricial animals have profound tolerance to hypothermia, but depend on parental care for warmth, whereas precocial mammals are well insulated and respond to cold with non-shivering thermogenesis in brown adipose tissue, and precocial birds shiver to produce heat. Most polar animals prepare themselves for shortness of food during winter by the deposition of large amounts of fat in times of plenty during autumn. These deposits are governed by a sliding set-point for body fatness throughout winter so that they last until the sun reappears in spring. Polar animals are, like most others, primarily active during the light part of the day, but when the sun never sets in summer and darkness prevails during winter, high-latitude animals become intermittently active around the clock, allowing opportunistic feeding at all times. The importance of understanding the needs of the individuals of a species to understand the responses of populations in times of climate change is emphasized.
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Affiliation(s)
- Arnoldus Schytte Blix
- Department of Arctic Biology, University of Tromsø, Tromsø 9037, Norway St Catharine's College, Cambridge CB2 1RL, UK
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Jensen B, Storz JF, Fago A. Bohr effect and temperature sensitivity of hemoglobins from highland and lowland deer mice. Comp Biochem Physiol A Mol Integr Physiol 2016; 195:10-4. [PMID: 26808972 DOI: 10.1016/j.cbpa.2016.01.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 01/30/2023]
Abstract
An important means of physiological adaptation to environmental hypoxia is an increased oxygen (O2) affinity of the hemoglobin (Hb) that can help secure high O2 saturation of arterial blood. However, the trade-off associated with a high Hb-O2 affinity is that it can compromise O2 unloading in the systemic capillaries. High-altitude deer mice (Peromyscus maniculatus) have evolved an increased Hb-O2 affinity relative to lowland conspecifics, but it is not known whether they have also evolved compensatory mechanisms to facilitate O2 unloading to respiring tissues. Here we investigate the effects of pH (Bohr effect) and temperature on the O2-affinity of high- and low-altitude deer mouse Hb variants, as these properties can potentially facilitate O2 unloading to metabolizing tissues. Our experiments revealed that Bohr factors for the high- and low-altitude Hb variants are very similar in spite of the differences in O2-affinity. The Bohr factors of deer mouse Hbs are also comparable to those of other mammalian Hbs. In contrast, the high- and low-altitude variants of deer mouse Hb exhibited similarly low temperature sensitivities that were independent of red blood cell anionic cofactors, suggesting an appreciable endothermic allosteric transition upon oxygenation. In conclusion, high-altitude deer mice have evolved an adaptive increase in Hb-O2 affinity, but this is not associated with compensatory changes in sensitivity to changes in pH or temperature. Instead, it appears that the elevated Hb-O2 affinity in high-altitude deer mice is compensated by an associated increase in the tissue diffusion capacity of O2 (via increased muscle capillarization), which promotes O2 unloading.
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Affiliation(s)
- Birgitte Jensen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark.
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA.
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark.
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Weber RE, Fago A, Campbell KL. Enthalpic partitioning of the reduced temperature sensitivity of O2 binding in bovine hemoglobin. Comp Biochem Physiol A Mol Integr Physiol 2014; 176:20-5. [PMID: 24983927 DOI: 10.1016/j.cbpa.2014.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/09/2014] [Accepted: 06/19/2014] [Indexed: 11/19/2022]
Abstract
The oxygenation enthalpy of the heme groups of hemoglobin (Hb) is inherently exothermic, resulting in decreased Hb-O2 affinity with rising temperature. However, oxygenation is coupled with endothermic dissociation of allosteric effectors (e.g. protons, chloride ions and organic phosphates) from the protein, which reduces the overall oxygenation enthalpy. The evolution of Hbs with reduced temperature sensitivity ostensibly safeguards O2 unloading in cold extremities of regionally-heterothermic vertebrates permitting energy-saving reductions in heat loss. Ungulate (e.g. bovine) Hbs have long served as a model system in this regard in that they exhibit numerically low oxygenation enthalpies that are thought to correlate with the presence of an additional Cl(-) binding site (compared to human Hb) comprised of three cationic residues at positions 8, 76 and 77 of the β-chains of Hb. However, ungulate Hbs also exhibit distinctive amino acid exchanges at the N-termini of the β-chains that stabilize the low-affinity deoxystructure of the Hb, mimicking the action of organic phosphates. In order to assess the relative contributions from these two effects, we measured the temperature sensitivity of Hb-O2 affinity in bovine and human Hbs in the absence and presence of Cl(-) ions under strictly controlled pH conditions. The data indicate that Cl(-)-binding accounts for a minority (~30%) of the total reduction in the oxygenation enthalpy manifested in bovine compared to human Hb, whereas the majority of this reduction is ascribable to structural differences, including increased β-chain hydrophobicity that would increase the heat of oxygenation-linked conformational change in bovine Hb.
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Affiliation(s)
- Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, DK 8000 Aarhus C, Denmark.
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, DK 8000 Aarhus C, Denmark.
| | - Kevin L Campbell
- Department of Biological Sciences, University of Manitoba, Winnipeg R3T 2N2, Canada.
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Enthalpic consequences of reduced chloride binding in Andean frog (Telmatobius peruvianus) hemoglobin. J Comp Physiol B 2014; 184:613-21. [DOI: 10.1007/s00360-014-0823-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/28/2014] [Accepted: 03/02/2014] [Indexed: 10/25/2022]
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Weber RE, Campbell KL. Temperature dependence of haemoglobin-oxygen affinity in heterothermic vertebrates: mechanisms and biological significance. Acta Physiol (Oxf) 2011; 202:549-62. [PMID: 20958923 DOI: 10.1111/j.1748-1716.2010.02204.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
As demonstrated by August Krogh et al. a century ago, the oxygen-binding reaction of vertebrate haemoglobin is cooperative (described by sigmoid O(2) equilibrium curves) and modulated by CO(2) and protons (lowered pH) that - in conjunction with later discovered allosteric effectors (chloride, lactate and organic phosphate anions) - enhance O(2) unloading from blood in relatively acidic and oxygen-poor tissues. Based on the exothermic nature of the oxygenation of the haem groups, haemoglobin-O(2) affinity also decreases with rising temperature. This thermal sensitivity favours oxygen unloading in warm working muscles, but may become detrimental in regionally heterothermic animals, for example in cold-tolerant birds and mammals and warm-bodied fish, where it may perturb the balance between O(2) unloading and O(2) requirement in organs with substantially different temperatures than at the respiratory organs and thus commonly is reduced or obliterated. Given that the oxygenation of haemoglobin is linked with the endothermic release of allosteric effectors, increased effector interaction is an effective strategy that is widely exploited to achieve adaptive reductions in the temperature dependence of blood-O(2) affinity. The molecular mechanisms implicated in heterothermic vertebrates from different taxonomic groups reveal remarkable variability, both as regards the effectors implicated (protons in tunas, organic phosphates in sharks and billfish, chloride ions in ruminants and chloride and phosphate anions in the extinct woolly mammoth, etc.) and binding sites for the same effectors, indicating multiple evolutionary origins, but convergent physiological functionality (reductions in temperature dependence of O(2) -binding affinity that safeguard tissue O(2) supply).
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Affiliation(s)
- R E Weber
- Zoophysiology, Institute of Biological Sciences, University of Aarhus, Aarhus, Denmark.
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Campbell KL, Storz JF, Signore AV, Moriyama H, Catania KC, Payson AP, Bonaventura J, Stetefeld J, Weber RE. Molecular basis of a novel adaptation to hypoxic-hypercapnia in a strictly fossorial mole. BMC Evol Biol 2010; 10:214. [PMID: 20637064 PMCID: PMC2927915 DOI: 10.1186/1471-2148-10-214] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2010] [Accepted: 07/16/2010] [Indexed: 11/25/2022] Open
Abstract
Background Elevated blood O2 affinity enhances survival at low O2 pressures, and is perhaps the best known and most broadly accepted evolutionary adjustment of terrestrial vertebrates to environmental hypoxia. This phenotype arises by increasing the intrinsic O2 affinity of the hemoglobin (Hb) molecule, by decreasing the intracellular concentration of allosteric effectors (e.g., 2,3-diphosphoglycerate; DPG), or by suppressing the sensitivity of Hb to these physiological cofactors. Results Here we report that strictly fossorial eastern moles (Scalopus aquaticus) have evolved a low O2 affinity, DPG-insensitive Hb - contrary to expectations for a mammalian species that is adapted to the chronic hypoxia and hypercapnia of subterranean burrow systems. Molecular modelling indicates that this functional shift is principally attributable to a single charge altering amino acid substitution in the β-type δ-globin chain (δ136Gly→Glu) of this species that perturbs electrostatic interactions between the dimer subunits via formation of an intra-chain salt-bridge with δ82Lys. However, this replacement also abolishes key binding sites for the red blood cell effectors Cl-, lactate and DPG (the latter of which is virtually absent from the red cells of this species) at δ82Lys, thereby markedly reducing competition for carbamate formation (CO2 binding) at the δ-chain N-termini. Conclusions We propose this Hb phenotype illustrates a novel mechanism for adaptively elevating the CO2 carrying capacity of eastern mole blood during burst tunnelling activities associated with subterranean habitation.
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Affiliation(s)
- Kevin L Campbell
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada.
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Clementi ME, Condò SG, Castagnola M, Giardina B. Hemoglobin function under extreme life conditions. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:309-17. [PMID: 7519981 DOI: 10.1111/j.1432-1033.1994.tb18996.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Considering the variety of species that depend on hemoglobin for oxygen transport, these molecules must execute their primary function under extreme environmental conditions. Hence, a thermodynamic analysis of oxygen binding with hemoglobins from different species reveals a series of adaptive mechanisms which are based on the thermodynamic connection between the binding of heterotropic effectors and the reaction with oxygen. The examples reported, from fishes to human fetus, illustrate how evolution can alter the structural basis of the heterotropic interactions to optimize the oxygenation-deoxygenation cycle in dependence of the physiological needs of the particular organisms. Moreover they show that a thermodynamic analysis of the reaction with oxygen overcomes the meaning of a detailed structural and functional characterization going deeper into the physiology of the specific organism.
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Affiliation(s)
- M E Clementi
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Italy
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15
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Giardina B, Galtieri A, Lania A, Ascenzi P, Desideri A, Cerroni L, Condo SG. Reduced sensitivity of O2 transport to allosteric effectors and temperature in loggerhead sea turtle hemoglobin: functional and spectroscopic study. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1159:129-33. [PMID: 1327156 DOI: 10.1016/0167-4838(92)90016-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The functional and spectroscopic (EPR and absorbance) properties of the adult loggerhead sea turtle (Caretta caretta) hemoglobin have been studied with special reference to the action of allosteric effectors and temperature. Present results indicate that turtle Hb displays a very low O2 affinity and a very small sensitivity to allosteric effectors and temperature. Furthermore, the amplitude of the Bohr effect for O2 binding is strongly reduced. In parallel, EPR and absorbance spectroscopic properties of the nitrosylated derivative of turtle Hb suggest that the hemoprotein is in a low-affinity conformation, even in the absence of allosteric effectors. These findings suggest the existence of unusual molecular mechanisms modulating the basic reaction of Hb with O2, which may be linked to specific physiological needs related to the diving behavior of the turtle.
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Affiliation(s)
- B Giardina
- Institute of Chemistry, Faculty of Medicine, Catholic University, Rome, Italy
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16
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Coletta M, Clementi ME, Ascenzi P, Petruzzelli R, Condò SG, Giardina B. A comparative study of the temperature dependence of the oxygen-binding properties of mammalian hemoglobins. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 204:1155-7. [PMID: 1551393 DOI: 10.1111/j.1432-1033.1992.tb16741.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effect of temperature on the oxygen-binding properties of hemoglobin (Hb) from ruminants, such as ox, reindeer, musk ox, mouflon and egyptian water buffalo is compared to that of human adult Hb (HbA). A striking difference emerges where in the presence of chloride ions and in the absence of 2,3-diphosphoglycerate [Gri(2,3)P2] a strongly reduced exothermic oxygenation process is observed for all ruminant Hb investigated with respect to HbA. Next, in the presence of physiological concentrations of Gri(2,3)P2, HbA displays a less exothermic oxygenation process, with values tending toward those observed in ruminant Hb [where Gri(2,3)P2 is not a physiological effector and for which the addition of Gri(2,3)P2 has essentially no effect on the oxygenation enthalpy]. Different from HbA, the intrinsically less exothermic oxygen binding seems to be independent of the experimental conditions for ruminant Hb, underlying specific structural characteristics which might be responsible for this feature.
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Affiliation(s)
- M Coletta
- Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy
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17
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Abstract
Evolution has adopted different strategies to solve the problem of transporting oxygen to respiring tissues, according to needs dictated by the environment. A thermodynamic analysis of haemoglobins of organisms living in extreme polar environments (mammals and fish) provides elegant examples of such adaptations.
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Affiliation(s)
- G di Prisco
- Institute of Protein Biochemistry and Enzymology, CNR, Naples, Italy
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18
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Abstract
The functional properties of hemoglobin from Egyptian water buffalo have been characterized as a function of pH, temperature and chloride concentration. Alongside overall similarities shared with ox and Arctic ruminant hemoglobins, hemoglobin from buffalo shows significant differences with respect to the effect of temperature. The results obtained may suggest that the limited effect of temperature on oxygen binding recently reported for ox hemoglobin could be regarded as an interesting case of a reminiscence of a past glacial age.
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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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