Peroxynitrite scavenging by ferrous truncated hemoglobin GlbO from Mycobacterium leprae

Paolo Ascenzi, Mario Milani, Paolo Visca

Research output: Contribution to journalArticlepeer-review

Abstract

Mycobacterium leprae GlbO has been proposed to represent merging of both O2 uptake/transport and scavenging of nitrogen reactive species. Peroxynitrite reacts with M. leprae GlbO(II)-NO leading to GlbO(III) via the GlbO(III)-NO species. The value of the second order rate constant for GlbO(III)-NO formation is >1 × 108 M-1 s-1 in the absence and presence of CO2 (1.2 × 10-3 M). The CO2-independent value of the first order rate constant for GlbO(III)-NO denitrosylation is (2.5 ± 0.4) × 101 s-1. Furthermore, peroxynitrite reacts with GlbO(II)-O2 leading to GlbO(III) via the GlbO(IV){double bond, long}O species. Values of the second order rate constant for GlbO(IV){double bond, long}O formation are (4.8 ± 0.5) × 104 and (6.3 ± 0.7) × 105 M-1 s-1 in the absence and presence of CO2 (=1.2 × 10-3 M), respectively. The value of the second order rate constant for the peroxynitrite-mediated GlbO(IV){double bond, long}O reduction (= (1.5 ± 0.2) × 104 M-1 s-1) is CO2-independent. These data argue for a role of GlbO in the defense of M. leprae against nitrosative stress.

Original languageEnglish
Pages (from-to)528-533
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume351
Issue number2
DOIs
Publication statusPublished - Dec 15 2006

Keywords

  • Carbon dioxide
  • GlbO
  • Mycobacterium leprae
  • Peroxynitrite
  • Scavenging of nitrogen reactive species
  • Truncated hemoglobin

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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