SEQUENCE-ANALYSIS AND TISSUE EXPRESSION OF A NON-BOHR BETA-GLOBIN CDNA FROM ATLANTIC SALMON

The presence of a haemoglobin protein which does not exhibit a Bohr ef fect has been found only in fish living in fast flowing waters. We rep ort the cloning of the first non-Bohr effect beta-globin cDNA from an adult Atlantic salmon kidney bank. Nucleotide sequence analysis of thi s cDNA shows that the predicted beta-globin peptide comprises 147 amin o acids with a calculated molecular mass of 15 975 Da and an overall a mino acid homology of 40 to 50% to higher vertebrates and 60-90% to fi sh sequences. This sequence confirms the important amino acid residues which are changed thus causing loss of the Bohr effect [Powers, D.A. and Edmunson, A.B. (1972) Multiple hemoglobins of catostomid fish. J. Biol. Chem. 247, 6686-6693; Brunori, M. (1975) Molecular adaptation to physiological requirements: the hemoglobin system of trout. Curr. Top ics Cell. Regul. 9, 1-39]. This loss allows the haemoglobin protein to have a higher oxygen affinity, as it does not release oxygen when the pH of the surrounding environment decreases, which is an important ab ility for the fish in times of stress. (C) 1997 Elsevier Science B.V.