Allosteric regulation of crocodilian haemoglobin

Perutz, M. F.; Bauer, Christian; Gros, Gerolf; Leclercq, F.; C, Vandecasserie; Schnek, Arthur G.; Braunitzer, Gerhard; Friday, Adrian; Joysey, K. A.

doi:10.1038/291682a0

Cited by 59 publications

(34 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, analysis of newly available sequences from a gene that has long supported a bird-mammal relationship, 3-hemoglobin, no longer supports that relationship. Instead, the anomalous position ofthe alligator agrees with the suggestion that the unusual allosteric properties of crocodilian 3-hemoglobin may have obscured an ancestry with birds (25,26).…”

Section: Discussionsupporting

confidence: 63%

Molecular evidence for the origin of birds.

Hedges

1994

Proc. Natl. Acad. Sci. U.S.A.

235

113

View full text Add to dashboard Cite

The major groups of amniote vertebrates appeared during a relatively short time span at the end of the Paleozoic Era, a fact that has caused difficulty in estimating their relationships. The fossil record suggests that crocodilans are the closest living relatives ofbirds. However, morphological characters and molecular sequence data from living amniotes have repeatedly chaflenged this hypothesis by indicating a bird-mammal relationship. DNA sequences from four slowevolving genes (mitochondrial 12S and 16S rRNA, tRNAVaI, and nuclear a-enolase) now provide strong statistical support for a bird-crocodillan relationship.

show abstract

Section: Discussionsupporting

confidence: 63%

Molecular evidence for the origin of birds.

Hedges

1994

Proc. Natl. Acad. Sci. U.S.A.

235

113

View full text Add to dashboard Cite

show abstract

“…Although most of the morphological and physiological criteria supporting the grouping of these endothermic amniotes could be refuted as shared derived characters (Kemp 1988), the concept of Haemothermia has found support unexpectedly often in phylogenetic reconstructions using sequences of myoglobin and ␤-hemoglobin (Goodman et al 1987;Bishop and Friday 1988), 18S rRNA (Hedges et al 1990), and tandemly aligned ␣/␤-hemoglobin sequences (Czelusniak et al 1990). However, some topologies of ␣-hemoglobin (Perutz et al 1981;Goodman et al 1987; but not Bishop and Friday 1988), ␣-crystallin A (Stapel et al 1984;de Jong et al 1985), and a multialignment of six protein sequences (Goodman et al 1987) have supported an Archosauria (i.e., crocodilians + birds) instead. The union of crocodiles and birds as closest relatives also has been obtained by nucleotide sequences from one nuclear and three mitochondrial genes and was found to represent the consensus of most amniote sequence data known to date (Hedges 1994).…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic Analysis of Reptilian Hemoglobins: Trees, Rates, and Divergences

1998

View full text Add to dashboard Cite

Phylogenetic relationships among reptiles were examined using previously published and newly determined hemoglobin sequences. Trees reconstructed from these sequences using maximum-parsimony, neighbor-joining, and maximum-likelihood algorithms were compared with a phylogenetic tree of Amniota, which was assembled on the basis of published morphological data. All analyses differentiated alpha chains into alphaA and alphaD types, which are present in all reptiles except crocodiles, where only alphaA chains are expressed. The occurrence of the alphaD chain in squamates (lizards and snakes only in this study) appears to be a general characteristic of these species. Lizards and snakes also express two types of beta chains (betaI and betaII), while only one type of beta chain is present in birds and crocodiles. Reconstructed hemoglobin trees for both alpha and beta sequences did not yield the monophyletic Archosauria (i.e., crocodilians + birds) and Lepidosauria (i.e., Sphenodon + squamates) groups defined by the morphology tree. This discrepancy, as well as some other poorly resolved nodes, might be due to substantial heterogeneity in evolutionary rates among single hemoglobin lineages. Estimation of branch lengths based on uncorrected amino acid substitutions and on distances corrected for multiple substitutions (PAM distances) revealed that relative rates for squamate alphaA and alphaD chains and crocodilian beta chains are at least twice as high as those of the rest of the chains considered. In contrast to these rate inequalities between reptilian orders, little variation was found within squamates, which allowed determination of absolute evolutionary rates for this subset of hemoglobins. Rate estimates for hemoglobins of lizards and snakes yielded 1.7 (alphaA) and 3.3 (beta) million years/PAM when calibrated with published divergence time vs. PAM distance correlates for several speciation events within snakes and for the squamate left and right arrow sphenodontid split. This suggests that hemoglobin chains of squamate reptiles evolved approximately 3.5 (alphaA) or approximately 1.7 times (beta) faster than their mammalian equivalents. These data also were used to obtain a first estimate of some intrasquamate divergence times.

show abstract

“…The complete sequence of the Hb from caiman [40] shows 102 substitutions with respect to human hemoglobin. Perutz et al have clearly shown [41] that only a few of these substitutions may explain the changes in allosteric control abolishing or weakening the binding sites for the usual allosteric effectors and creating a new pair of binding sites which are complementary to bicarbonate ions in the deoxy structure (T state) but not in the oxy structure (R state).…”

Section: Turtle Penguin and Caimanmentioning

confidence: 99%

“…The proposed stereochemical model [41] shows the N-terminal serine of caiman Hb within exact reach of the bicarbonate ion so that one of the bicarbonate oxygens forms a salt bridge with the a-NH: and can also accept a rather long hydrogen bond from the serine OH. The second bicarbonate oxygen forms a salt bridge with Lys EF6(82) and the third oxygen donates a hydrogen bond to one of the carboxylate oxygens of Glu H22(144j.…”

Section: Turtle Penguin and Caimanmentioning

confidence: 99%

Hemoglobin function under extreme life conditions

Clementi

Condò

Castagnola

et al. 1994

European Journal of Biochemistry

View full text Add to dashboard Cite

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.Respiratory pigments directly link external conditions with body requirements and are therefore interesting systems for studying the effect of the environment on molecular evolution. Considering the variety of species that depend on hemoglobin for oxygen transport, these molecules must execute their primary function under extreme environmental conditions. Hence, the hemoglobins have experienced a major evolutionary pressure which has led to the development of a number of complex regulatory mechanisms operative at the molecular level and designed to fulfil the physiological requirements of a given species.All vertebrate hemoglobins exhibit a marked degree of cooperativity between subunits or 'heme-heme' interaction (homotropic interactions) which enables maximum oxygen unloading at relatively high oxygen tension. In the simple model, cooperativity in oxygen binding is achieved through the conformational transition, between the deoxy-low-affinity state (or T state) and the oxy-high-affinity state (or R state), which accounts for the sigmoidal shape of the oxygen binding curve. In addition, the oxygen affinity of hemoglobin is affected by several metabolic effectors (heterotropic interactions) such as chloride, protons (Bohr effect), CO, and organic phosphates. Under physiological conditions, in fact, all these effectors bind preferentially to the deoxy conformation (T state) of hemoglobin thereby shifting the allosteric Correspondence to B . Giardina, Istituto di Chimica, Universith Cattolica del "Sacro Cuore", Largo F. equilibrium ( T o R ) towards the T state and lowering the overall 0, affinity of the molecule. The modulation of function induced by these effectors has important physiological effects. For example, at the level of respiring tissues, the decrease of 0, affinity brought about by the increase in proton activity (alkaline Bohr effect) allows a more efficient unloading of 0, and contributes to the neutralization of protons produced by CO, and lactic acid.Another important feature of the reaction of hemoproteins with 0, is its temperature dependence which is governed by the associated overall enthalpy change (AH). Oxyge...

show abstract

Allosteric regulation of crocodilian haemoglobin

Cited by 59 publications

References 19 publications

Molecular evidence for the origin of birds.

Molecular evidence for the origin of birds.

Phylogenetic Analysis of Reptilian Hemoglobins: Trees, Rates, and Divergences

Hemoglobin function under extreme life conditions

Contact Info

Product

Resources

About