title: A biochemical--biophysical study of hemoglobins from woolly mammoth, Asian elephant, and humans.
abstract: This study is aimed at investigating the molecular basis of environmental adaptation of woolly mammoth hemoglobin (Hb) to the harsh thermal conditions of the Pleistocene ice ages. To this end, we have carried out a comparative biochemical-biophysical characterization of the structural and functional properties of recombinant hemoglobins (rHb) from woolly mammoth (rHb WM) and Asian elephant (rHb AE) in relation to human hemoglobins Hb A and Hb A(2) (a minor component of human blood). We have obtained oxygen equilibrium curves and calculated O(2) affinities, Bohr effects, and the apparent heat of oxygenation (ΔH) in the presence and absence of allosteric effectors [inorganic phosphate and inositol hexaphosphate (IHP)]. Here, we show that the four Hbs exhibit distinct structural properties and respond differently to allosteric effectors. In addition, the apparent heat of oxygenation (ΔH) for rHb WM is less negative than that of rHb AE, especially in phosphate buffer and the presence of IHP, suggesting that the oxygen affinity of mammoth blood was also less sensitive to temperature change. Finally, (1)H NMR spectroscopy data indicates that both α(1)(β/δ)(1) and α(1)(β/δ)(2) interfaces in rHb WM and rHb AE are perturbed, whereas only the α(1)δ(1) interface in Hb A(2) is perturbed compared to that in Hb A. The distinct structural and functional features of rHb WM presumably facilitated woolly mammoth survival in the Arctic environment.
authors.affiliation: Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Yue
authors.initials: Y
authors.lastname: Yuan
authors.forename: Tong-Jian
authors.initials: TJ
authors.lastname: Shen
authors.forename: Priyamvada
authors.initials: P
authors.lastname: Gupta
authors.forename: Nancy T
authors.initials: NT
authors.lastname: Ho
authors.forename: Virgil
authors.initials: V
authors.lastname: Simplaceanu
authors.forename: Tsuey Chyi S
authors.initials: TC
authors.lastname: Tam
authors.forename: Michael
authors.initials: M
authors.lastname: Hofreiter
authors.forename: Alan
authors.initials: A
authors.lastname: Cooper
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Campbell
authors.forename: Chien
authors.initials: C
authors.lastname: Ho
mesh_terms: D017738:Alkanesulfonic Acids / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D055592:Biophysical Phenomena; D001802:Blood Substitutes / Q000378:metabolism; D002021:Buffers; D004606:Elephants; D006443:Hemoglobin A2 / Q000737:chemistry / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D056665:Mammoths; D008969:Molecular Sequence Data; D009025:Morpholines / Q000737:chemistry; D010100:Oxygen / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry; D013696:Temperature
chemical_list: D017738:Alkanesulfonic Acids; D001802:Blood Substitutes; D002021:Buffers; D006454:Hemoglobins; D009025:Morpholines; D010710:Phosphates; C004550:2-(N-morpholino)ethanesulfonic acid; D006443:Hemoglobin A2; D010100:Oxygen