The amino acid sequence and oxygen-binding properties of the single hemoglobin of the cold-adapted Antarctic teleost Gymnodraco acuticeps.

Institute of Protein Biochemistry and Enzymology, C.N.R., Naples, Italy.
Archives of Biochemistry and Biophysics (Impact Factor: 3.04). 02/1992; 292(1):295-302. DOI: 10.1016/0003-9861(92)90082-8
Source: PubMed

ABSTRACT The complete amino acid sequence of the single hemoglobin of the Antarctic teleost Gymnodraco acuticeps has been determined. The alpha chain contains 142 amino acid residues; an acetylated seryl residue is at the amino terminal. The beta chain contains 146 residues. A very high degree of sequence identity has been found with hemoglobins of other Antarctic fishes. Oxygen binding is not modulated by pH and allosteric effectors. The Bohr and Root effects are absent, although specific amino acid residues, considered responsible of most of these functions, are conserved in the sequence, thus posing new questions about the molecular basis of these mechanisms. The low heat of oxygenation may be interpreted as one of the mechanisms involved in the process of cold adaptation.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Two α- and two β-globin genes from the yellowtail were cloned and their nucleotide sequences determined. The entire open reading frames of α-globin A and B genes were 432 and 435 bp long, respectively, whereas the corresponding values of the yellowtail β-globin A and B genes were both 447 bp. Amino acid identity of the yellowtail α- or β-globin gene compared with those reported in other vertebrates including shark, teleosts and human, ranged from 35.4 to 83.0%. The yellowtail α-globin B has a unique inserted amino acid residue in the 48th position, not found in other fish α-globin genes. The orientation of α- and β-globin genes open reading frames was head-to-head.
    Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology 01/2001; 130(2):207-216. · 1.90 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hemoglobin components (isohemoglobins) and their isoelectric points (pI) were analysed for three herbivorous marine teleosts, and the functional properties of their unfractionated, stripped hemolysates were determined. Kyphosus sydneyanus and Girella tricuspidata possess six isohemoglobins and share a dominant cathodic band (pI=8.61). Odax pullus possesses four isohemoglobins characterised by two strongly anodic bands (pI=5.80, 4.89). Equilibrium binding studies of the hemolysate complexes from K. sydneyanus and G. tricuspidata revealed high oxygen affinities which were relatively insensitive to pH, whereas oxygen affinity was markedly lower and more pH sensitive in O. pullus. Moreover, hemoglobin-oxygen affinity was less temperature-sensitive in K. sydneyanus than in O. pullus. These observations support the hypothesis that hemoglobin oxygen loading in the cool-temperate species (O. pullus) may be compromised in the most northerly (warm) limits of its distribution, and that ecologically equivalent species in warmer and thermally variable habitats (K. sydneyanus and G. tricuspidata) possess more cathodic isohemoglobins which are less influenced by pH and temperature.
    Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 10/1998; 121(2):189-195. · 2.37 Impact Factor
  • Fish Physiology. 01/2005; 22:281-316.