Effect of NH2-terminal acetylation on the oxygenation properties of vertebrate haemoglobin

Chandrasekhar Natarajan, Anthony V. Signore, Vikas Kumar, Roy E. Weber, Angela Fago, Jay F. Storz

Research output: Contribution to journalArticlepeer-review

Abstract

In vertebrate haemoglobin (Hb), the NH2-terminal residues of the α- and β-chain subunits are thought to play an important role in the allosteric binding of protons (Bohr effect), CO2 (as carbamino derivatives), chloride ions, and organic phosphates. Accordingly, acetylation of the α- and/or β-chain NH2-termini may have significant effects on the oxygenation properties of Hb. Here we investigate the effect of NH2-terminal acetylation by using a newly developed expression plasmid system that enables us to compare recombinantly expressed Hbs that are structurally identical except for the presence or absence of NH2-terminal acetyl groups. Experiments with native and recombinant Hbs of representative vertebrates reveal that NH2-terminal acetylation does not impair the Bohr effect, nor does it significantly diminish responsiveness to allosteric cofactors, such as chloride ions or organic phosphates. These results suggest that observed variation in the oxygenation properties of vertebrate Hbs is principally explained by amino acid divergence in the constituent globin chains rather than post-translational modifications of the globin chain NH2-termini.

Original languageEnglish (US)
Pages (from-to)3839-3850
Number of pages12
JournalThe Biochemical journal
Volume477
Issue number19
DOIs
StatePublished - Oct 16 2020

Keywords

  • amino-terminal acetylation
  • Bohr effect
  • oxygen binding
  • post-translational modification
  • recombinant hemoglobin

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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