A cooperative oxygen-binding hemoglobin from Mycobacterium tuberculosis

Manon Couture, Syun-Ru Yeh, Beatrice A. Wittenberg, Jonathan B. Wittenberg, Yannick Ouellet, Denis L. Rousseau, Michel Guertin

Research output: Contribution to journalArticle

189 Citations (Scopus)

Abstract

Two putative hemoglobin genes, glbN and glbO, were recently discovered in the complete genome sequence of Mycobacterium tuberculosis H37Rv. Here, we show that the glbN gene encodes a dimeric hemoglobin (HbN) that binds oxygen cooperatively with very high affinity (P50 = 0.013 mmHg at 20 °C) because of a fast combination (25 μM-1 · s-1) and a slow dissociation (0.2 s- 1) rate. Resonance Raman spectroscopy and ligand association/dissociation kinetic measurements, along with mutagenesis studies, reveal that the stabilization of the bound oxygen is achieved through a tyrosine at the B10 position in the distal pocket of the heme with a conformation that is unique among the globins. Physiological studies performed with Mycobacterium bovis bacillus Calmette-Guerin demonstrate that the expression of HbN is greatly enhanced during the stationary phase in aerobic cultures but not under conditions of limited oxygen availability. The results suggest that, physiologically, the primary role of HbN may be to protect the bacilli against reactive nitrogen species produced by the host macrophage.

Original languageEnglish (US)
Pages (from-to)11223-11228
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number20
DOIs
StatePublished - Sep 28 1999

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Mycobacterium tuberculosis
Hemoglobins
Oxygen
Mycobacterium bovis
Reactive Nitrogen Species
Globins
Raman Spectrum Analysis
Heme
Mutagenesis
Bacillus
Genes
Tyrosine
Macrophages
Genome
Ligands

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

A cooperative oxygen-binding hemoglobin from Mycobacterium tuberculosis. / Couture, Manon; Yeh, Syun-Ru; Wittenberg, Beatrice A.; Wittenberg, Jonathan B.; Ouellet, Yannick; Rousseau, Denis L.; Guertin, Michel.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 96, No. 20, 28.09.1999, p. 11223-11228.

Research output: Contribution to journalArticle

Couture, Manon ; Yeh, Syun-Ru ; Wittenberg, Beatrice A. ; Wittenberg, Jonathan B. ; Ouellet, Yannick ; Rousseau, Denis L. ; Guertin, Michel. / A cooperative oxygen-binding hemoglobin from Mycobacterium tuberculosis. In: Proceedings of the National Academy of Sciences of the United States of America. 1999 ; Vol. 96, No. 20. pp. 11223-11228.
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