title: Structure, function and molecular adaptations of haemoglobins of the polar cartilaginous fish Bathyraja eatonii and Raja hyperborea.
abstract: Cartilaginous fish are very ancient organisms. In the Antarctic sea, the modern chondrichthyan genera are poorly represented, with only three species of sharks and eight species of skates; the paucity of chondrichthyans is probably an ecological consequence of unusual trophic or habitat conditions in the Southern Ocean. In the Arctic, there are 26 species belonging to the class Chondrichthyes. Fish in the two polar regions have been subjected to different regional histories that have influenced the development of diversity: Antarctic marine organisms are highly stenothermal, in response to stable water temperatures, whereas the Arctic communities are exposed to seasonal temperature variations. The structure and function of the oxygen-transport haem protein from the Antarctic skate Bathyraja eatonii and from the Arctic skate Raja hyperborea (both of the subclass Elasmobranchii, order Rajiformes, family Rajidae) is reported in the present paper. These species have a single major haemoglobin (Hb 1; over 80% of the total). The Bohr-proton and the organophosphate-binding sites are absent. Thus the haemoglobins of northern and southern polar skates appear functionally similar, whereas differences were observed with several temperate elasmobranchs. Such evidence suggests that, in temperate and polar habitats, physiological adaptations have evolved along distinct pathways, whereas, in this case, the effect of the differences characterizing the two polar environments is negligible.
authors.affiliation: Institute of Protein Biochemistry, CNR, Via Marconi 12, I-80125 Naples, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Verde
authors.forename: M Cristina
authors.initials: MC
authors.lastname: De Rosa
authors.forename: Daniela
authors.initials: D
authors.lastname: Giordano
authors.forename: Donato
authors.initials: D
authors.lastname: Mosca
authors.forename: Donatella
authors.initials: D
authors.lastname: De Pascale
authors.forename: Luca
authors.initials: L
authors.lastname: Raiola
authors.forename: Ennio
authors.initials: E
authors.lastname: Cocca
authors.forename: Vitale
authors.initials: V
authors.lastname: Carratore
authors.forename: Bruno
authors.initials: B
authors.lastname: Giardina
authors.forename: Guido
authors.initials: G
authors.lastname: Di Prisco
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000864:Antarctic Regions; D001110:Arctic Regions; D001665:Binding Sites; D006418:Heme / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010755:Organophosphates / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D012860:Skates, Fish / Q000235:genetics; D013816:Thermodynamics
chemical_list: D006454:Hemoglobins; D010755:Organophosphates; D006418:Heme; D010100:Oxygen