Studies on Yak Hemoglobin<i>(Bos grunniens,</i>Bovidae): Structural Basis for High Intrinsic Oxygen Affinity?

Lalthantluanga, Ralte; Wiesner, Henning; Braunitzer, Gerhard

doi:10.1515/bchm3.1985.366.1.63

Cited by 23 publications

(13 citation statements)

References 13 publications

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“…Others, llama, Guanaco and alpaca show a comparable high blood oxygen affinity that adapted to high altitude so smoothly, also caused by the substitution β2 (NA2) His→Asn (Marco et al, 1990). The substitution of Valine at position β135 (H13) in the β Π -chain may be responsible for the high intrinsic oxygen affinity of yak hemoglobin (Lalthantluanga et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

“…It is unique in its ability to adapt to a wide range of environmental conditions (Melo et al, 2003). Possession of a Hb with high oxygen affinity, which helps high altitude animals to adapt to high altitude, has been studied profoundly (Godovac-Zimmermann et al, 1988;Hiebl et al, 1987;Jessen et al, 1991;Kleinschmidt et al, 1986;Lalthantluanga et al, 1985;Weber et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Molecular cloning and characterization of hemoglobin α and β chains from plateau pika (Ochotona curzoniae) living at high altitude

Yang¹,

Cao²,

Jin³

et al. 2007

Gene

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular cloning and characterization of hemoglobin α and β chains from plateau pika (Ochotona curzoniae) living at high altitude

Yang¹,

Cao²,

Jin³

et al. 2007

Gene

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“…This high-affinity fetal hemoglobin is adapted to placental/tissue oxygen transport in the hypoxic intrauterine environment and apparently can be co-opted for pulmonary/tissue oxygen transport under conditions of hypoxic stress during postnatal life. In addition to the coexpression of fetal and adult hemoglobins under hypoxic conditions, yaks also possess multiple adult hemoglobin isoforms due to functional divergence among tandemly duplicated aand b-globin genes (Lalthantluanga et al 1985;Weber et al 1988b). Since yaks inhabit alpine environments at elevations of 3000-6000 m on the Tibetan Plateau, the cascaded oxygen affinities of the fetal and adult hemoglobin isoforms appear to play an important role in the hypoxia tolerance of these animals during both pre-and postnatal life.…”

Section: Discussionmentioning

confidence: 99%

Adaptive Functional Divergence Among Triplicated α-Globin Genes in Rodents

et al. 2008

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The functional divergence of duplicated genes is thought to play an important role in the evolution of new developmental and physiological pathways, but the role of positive selection in driving this process remains controversial. The objective of this study was to test whether amino acid differences among triplicated a-globin paralogs of the Norway rat (Rattus norvegicus) and the deer mouse (Peromyscus maniculatus) are attributable to a relaxation of purifying selection or to a history of positive selection that has adapted the gene products to new or modified physiological tasks. In each rodent species, the two paralogs at the 59-end of the a-globin gene cluster (HBA-T1 and HBA-T2) are evolving in concert and are therefore identical or nearly identical in sequence. However, in each case, the HBA-T1 and HBA-T2 paralogs are distinguished from the third paralog at the 39-end of the gene cluster (HBA-T3) by multiple amino acid substitutions. An analysis of genomic sequence data from several rodent species revealed that the HBA-T3 genes of Rattus and Peromyscus originated via independent, lineage-specific duplication events. In the independently derived HBA-T3 genes of both species, a likelihood analysis based on a codon-substitution model revealed that accelerated rates of amino acid substitution are attributable to positive directional selection, not to a relaxation of purifying selection. As a result of functional divergence among the triplicated a-globin genes in Rattus and Peromyscus, the red blood cells of both rodent species contain a mixture of functionally distinct a-chain hemoglobin isoforms that are predicted to have different oxygen-binding affinities. In P. maniculatus, a species that is able to sustain physiological function under conditions of chronic hypoxia at high altitude, the coexpression of distinct hemoglobin isoforms with graded oxygen affinities is expected to broaden the permissible range of arterial oxygen tensions for pulmonary/tissue oxygen transport.

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“…This high-affinity fetal Hb is adapted to placental-tissue O 2 transport in the hypoxic intrauterine environment and apparently can be coopted for pulmonary-tissue O 2 transport under hypoxic conditions during postnatal life. In addition to the coexpression of fetal and adult Hbs under hypoxic conditions, yaks also possess multiple adult isoHbs due to functional differentiation among tandemly duplicated ␣-and ␤-globin genes (Lalthantluanga et al, 1985;Weber et al, 1988b). Since yaks inhabit alpine environments at elevations of 3000 to 6000 m on the Tibetan Plateau, the cascaded O 2 affinities of the fetal and adult isoHbs appear to play an important role in the hypoxia tolerance of these animals during both pre-and postnatal life.…”

Section: Effects Of Hemoglobin Isoform Differentiation On Blood O 2 Tmentioning

confidence: 99%

Mechanisms of Hemoglobin Adaptation to High Altitude Hypoxia

Storz

Moriyama

2008

High Altitude Medicine & Biology

171

131

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Storz, Jay F., and Hideaki Moriyama. Mechanisms of hemoglobin adaptation. High Alt. Med. Biol. 9:148-157, 2008.-Evidence from a number of vertebrate taxa suggests that modifications of hemoglobin (Hb) function may often play a key role in mediating an adaptive response to high altitude hypoxia. The respiratory functions of Hb are a product of the protein's intrinsic O 2 -binding affinity and its interactions with allosteric effectors such as protons, chloride ions, CO 2 , and organic phosphates. Here we review several case studies involving high altitude vertebrates where it has been possible to identify specific mechanisms of Hb adaptation to hypoxia. In addition to comparative studies of Hbs from diverse animal species, functional studies of human Hb mutants also suggest that there is ample scope for evolutionary adjustments in Hb-O 2 affinity through alterations of the equilibrium constants of O 2 binding to deoxy-and oxyHb or through changes in the allosteric equilibrium constants for the transition between the deoxy-and oxyHb quaternary structures. It may be the case that certain evolutionary paths are followed more often than others simply because they are subject to less stringent pleiotropic constraints.

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Studies on Yak Hemoglobin(Bos grunniens,Bovidae): Structural Basis for High Intrinsic Oxygen Affinity?

Cited by 23 publications

References 13 publications

Molecular cloning and characterization of hemoglobin α and β chains from plateau pika (Ochotona curzoniae) living at high altitude

Molecular cloning and characterization of hemoglobin α and β chains from plateau pika (Ochotona curzoniae) living at high altitude

Adaptive Functional Divergence Among Triplicated α-Globin Genes in Rodents

Mechanisms of Hemoglobin Adaptation to High Altitude Hypoxia

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