Nature 293, 587 - 588 (15 October 1981); doi:10.1038/293587a0

Structure of binding sites for heterotropic effectors in fish haemoglobins

Donatella Barra, Francesco Bossa & Maurizio Brunori

Istituto di Chimica Biologica, Università di Camerino e di Roma, Italy
Istituto di Chimica, Facoltà di Medicina, Università di Roma, 00185 Roma, Italy
Centro di Biologia Molecolare del CNR, Roma, Italy

Haemoglobin binds oxygen cooperatively. In mammalian and bird haemoglobins the oxygen affinity is modulated by hydrogen and chloride ions, organic phosphates and CO₂ (ref. 1), and the amino acid residues responsible for these so-called heterotropic effects have been identified^2,3. In some fish haemoglobins these heterotropic effects are modified to adapt the fish to their specific habitats⁴. We have determined the functional properties and amino acid sequences of the haemoglobins in trout blood and in the Amazonian fish Pterygoplichthys pardalis (Pt HbI), which is a facultative air breather⁵⁻⁹. Trout HbI binds oxygen cooperatively, but shows no Bohr effect over the pH range 5−9 and no organic phosphate effect¹⁰. Pt HbI also binds oxygen cooperatively; its Bohr effect is small and reversed and its oxygen affinity is lowered by organic phosphates below pH 7.0−7.5 (ref. 9). Both haemoglobins represent substantial fractions of the total pigments in the red cells. We have now analysed the amino acid sequences of these two proteins to discover whether the particular residues thought to be responsible for the Bohr effect and organic phosphate binding in mammalian haemoglobins have been replaced by others in fish haemoglobins^6,7,11.

References

1.	Antonini, E. & Brunori, M. Hemoglobin and Myoglobin in their Reactions with Ligands (North-Holland, Amsterdam, 1971).
2.	Perutz, M. F. Br. med. Bull. 32, 195−208 (1976). | PubMed | ISI | ChemPort |
3.	Kilmartin, J. V. Br. med. Bull. 32, 209−212 (1976). | PubMed | ISI | ChemPort |
4.	Riggs, A. Fedn Proc. 35, 2115−2118 (1976). | ChemPort |
5.	Brunori, M. Curr. Topics cell. Regulation 9, 1−39 (1975). | ChemPort |
6.	Bossa, F. et al. FEBS Lett. 64, 76−80 (1976). | Article | PubMed | ISI | ChemPort |
7.	Bossa, F., Barra, D., Petruzzelli, R., Martini, F. & Brunori, M. Biochim. biophys. Acta 536, 298−305 (1978). | Article | PubMed | ISI | ChemPort |
8.	Riggs, A. Comp. Biochem. Physiol. 62A, 257−272 (1979). | Article | ISI |
9.	Brunori, M., Bonaventura, J., Focesi, A., Galdames-Portus, M. I. & Wilson, M. T. Comp. Biochem. Physiol. 62A, 173−177 (1979). | Article | ISI |
10.	Brunori, M., Falcioni, G., Fortuna, G. & Giardina, B. Archs Biochem. Biophys. 168, 512−519 (1975). | ChemPort |
11.	Savi, M. R., Barra, D., Amendola, K., Bossa, F. & Brunori, M. Proc. 26th Congr. SIB 195 (Lorenzini, Bologna, 1980).
12.	Nishikura, K. Biochem. J. 173, 651−657 (1978). | PubMed | ChemPort |
13.	Arnone, A. Nature 237, 146−149 (1972). | PubMed | ISI | ChemPort |
14.	Airoldi, L. P. da S., Brunori, M. & Giardina, B. FEBS Lett. 129, 273−276 (1981). | Article | PubMed | ISI | ChemPort |
15.	Matthew, J. B., Hanania, G. I. H. & Gurd, F. R. N. Biochemistry 18, 1919−1928, 1928−1936 (1979). | PubMed | ISI | ChemPort |
16.	Eaton, W. A. Nature 284, 183−185 (1980). | Article | PubMed | ISI | ChemPort |