Reductive nitrosylation of Methanosarcina acetivorans protoglobin: A comparative study

Paolo Ascenzi, Alessandra Pesce, Marco Nardini, Martino Bolognesi, Chiara Ciaccio, Massimo Coletta, Sylvia Dewilde

Research output: Contribution to journalArticlepeer-review


Methanosarcina acetivorans is a strictly anaerobic non-motile methane-producing Archaea expressing protoglobin (Pgb) which might either facilitate O2 detoxification or act as a CO sensor/supplier in methanogenesis. Unusually, M. acetivorans Pgb (MaPgb) binds preferentially O2 rather than CO and displays anticooperativity in ligand binding. Here, kinetics and/or thermodynamics of ferric and ferrous MaPgb (MaPgb(III) and MaPgb(II), respectively) nitrosylation are reported. Data were obtained between pH 7.2 and 9.5, at 22.0°C. Addition of NO to MaPgb(III) leads to the transient formation of MaPgb(III)-NO in equilibrium with MaPgb(II)-NO+. In turn, MaPgb(II)-NO+ is converted to MaPgb(II) by OH--based catalysis. Then, MaPgb(II) binds NO very rapidly leading to MaPgb(II)-NO. The rate-limiting step for reductive nitrosylation of MaPgb(III) is represented by the OH--mediated reduction of MaPgb(II)-NO+ to MaPgb(II). Present results highlight the potential role of MaPgb in scavenging of reactive nitrogen and oxygen species.

Original languageEnglish
Pages (from-to)1301-1305
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number4
Publication statusPublished - Jan 25 2013


  • Kinetics
  • Methanosarcina acetivorans protoglobin
  • Nitrosylation of ferrous Methanosarcina acetivorans protoglobin
  • Reductive nitrosylation of ferric Methanosarcina acetivorans protoglobin
  • Thermodynamics

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Molecular Biology


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