Reduced sensitivity of O2 transport to allosteric effectors and temperature in loggerhead sea turtle hemoglobin: functional and spectroscopic study

Bruno Giardina, Antonio Galtieri, Amalia Lania, Paolo Ascenzi, Alessandro Desideri, Loredana Cerroni, Saverio G. Condo

Research output: Contribution to journalArticlepeer-review

Abstract

The functional and spectroscopic (EPR and absorbance) properties of the adult loggerhead sea turtle (Caretta caretta) hemoglobin have been studied with special reference to the action of allosteric effectors and temperature. Present results indicate that turtle Hb displays a very low O2 affinity and a very small sensitivity to allosteric effectors and temperature. Furthermore, the amplitude of the Bohr effect for O2 binding is strongly reduced. In parallel, EPR and absorbance spectroscopic properties of the nitrosylated derivative of turtle Hb suggest that the hemoprotein is in low-affinity conformation, even in the absence of allosteric effectors. These findings suggest the existence of unusual molecular mechanisms modulating the basic reaction of Hb with O2, which may be linked to specific physiological needs related to the diving behavior of the turtle.

Original languageEnglish
Pages (from-to)129-133
Number of pages5
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Volume1159
Issue number2
DOIs
Publication statusPublished - Sep 23 1992

Keywords

  • (C. caretta)
  • (Sea turtle)
  • Absorbance
  • Allosteric effector
  • EPR
  • Hemoglobin
  • Temperature effect

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology
  • Structural Biology
  • Medicine(all)

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