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Oxygen binding to partially nitrosylated hemoglobin.

Publication ,  Journal Article
Fago, A; Crumbliss, AL; Hendrich, MP; Pearce, LL; Peterson, J; Henkens, R; Bonaventura, C
Published in: Biochimica et biophysica acta
September 2013

Reactions of nitric oxide (NO) with hemoglobin (Hb) are important elements in protection against nitrosative damage. NO in the vasculature is depleted by the oxidative reaction with oxy Hb or by binding to deoxy Hb to generate partially nitrosylated Hb (Hb-NO). Many aspects of the formation and persistence of Hb-NO are yet to be clarified. In this study, we used a combination of EPR and visible absorption spectroscopy to investigate the interactions of partially nitrosylated Hb with O2. Partially nitrosylated Hb samples had predominantly hexacoordinate NO-heme geometry and resisted oxidation when exposed to O2 in the absence of anionic allosteric effectors. Faster oxidation occurred in the presence of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate (IHP), where the NO-heme derivatives had higher levels of pentacoordinate heme geometry. The anion-dependence of the NO-heme geometry also affected O2 binding equilibria. O2-binding curves of partially nitrosylated Hb in the absence of anions were left-shifted at low saturations, indicating destabilization of the low O2 affinity T-state of the Hb by increasing percentages of NO-heme, much as occurs with increasing levels of CO-heme. Samples containing IHP showed small decreases in O2 affinity, indicating shifts toward the low-affinity T-state and formation of inert α-NO/β-met tetramers. Most remarkably, O2-equilibria in the presence of the physiological effector DPG were essentially unchanged by up to 30% NO-heme in the samples. As will be discussed, under physiological conditions the interactions of Hb with NO provide protection against nitrosative damage without impairing O2 transport by Hb's unoccupied heme sites. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.

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Published In

Biochimica et biophysica acta

DOI

EISSN

1878-2434

ISSN

0006-3002

Publication Date

September 2013

Volume

1834

Issue

9

Start / End Page

1894 / 1900

Related Subject Headings

  • Protein Binding
  • Phytic Acid
  • Oxyhemoglobins
  • Oxygen
  • Oxidation-Reduction
  • Nitric Oxide
  • Humans
  • Heme
  • Glycated Hemoglobin
  • Electron Spin Resonance Spectroscopy
 

Citation

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Fago, A., Crumbliss, A. L., Hendrich, M. P., Pearce, L. L., Peterson, J., Henkens, R., & Bonaventura, C. (2013). Oxygen binding to partially nitrosylated hemoglobin. Biochimica et Biophysica Acta, 1834(9), 1894–1900. https://doi.org/10.1016/j.bbapap.2013.04.017
Fago, Angela, Alvin L. Crumbliss, Michael P. Hendrich, Linda L. Pearce, Jim Peterson, Robert Henkens, and Celia Bonaventura. “Oxygen binding to partially nitrosylated hemoglobin.Biochimica et Biophysica Acta 1834, no. 9 (September 2013): 1894–1900. https://doi.org/10.1016/j.bbapap.2013.04.017.
Fago A, Crumbliss AL, Hendrich MP, Pearce LL, Peterson J, Henkens R, et al. Oxygen binding to partially nitrosylated hemoglobin. Biochimica et biophysica acta. 2013 Sep;1834(9):1894–900.
Fago, Angela, et al. “Oxygen binding to partially nitrosylated hemoglobin.Biochimica et Biophysica Acta, vol. 1834, no. 9, Sept. 2013, pp. 1894–900. Epmc, doi:10.1016/j.bbapap.2013.04.017.
Fago A, Crumbliss AL, Hendrich MP, Pearce LL, Peterson J, Henkens R, Bonaventura C. Oxygen binding to partially nitrosylated hemoglobin. Biochimica et biophysica acta. 2013 Sep;1834(9):1894–1900.

Published In

Biochimica et biophysica acta

DOI

EISSN

1878-2434

ISSN

0006-3002

Publication Date

September 2013

Volume

1834

Issue

9

Start / End Page

1894 / 1900

Related Subject Headings

  • Protein Binding
  • Phytic Acid
  • Oxyhemoglobins
  • Oxygen
  • Oxidation-Reduction
  • Nitric Oxide
  • Humans
  • Heme
  • Glycated Hemoglobin
  • Electron Spin Resonance Spectroscopy