Reductive nitrosylation of Methanosarcina acetivorans protoglobin: A comparative study
- Laboratorio Interdipartimentale di Microscopia Elettronica, Università Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy)
- Dipartimento di Fisica, Università di Genova, I-16146 Genova (Italy)
- Dipartimento di Bioscienze, Università di Milano, Via Celoria 26, I-20133 Milano (Italy)
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, I-00133 Roma (Italy)
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium)
Highlights: ► Methanosarcina acetivorans is a strictly anaerobic non-motile methane-producing Archaea. ► M. acetivorans protoglobin binds preferentially O{sub 2} rather than CO. ► Reductive nitrosylation of ferric M. acetivorans protoglobin. ► Nitrosylation of ferrious M. acetivorans protoglobin. ► M. acetivorans protoglobin is a scavenger of RNS and ROS. -- Abstract: Methanosarcina acetivorans is a strictly anaerobic non-motile methane-producing Archaea expressing protoglobin (Pgb) which might either facilitate O{sub 2} detoxification or act as a CO sensor/supplier in methanogenesis. Unusually, M. acetivorans Pgb (MaPgb) binds preferentially O{sub 2} 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{sup +}. In turn, MaPgb(II)–NO{sup +} is converted to MaPgb(II) by OH{sup −}-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{sup −}-mediated reduction of MaPgb(II)–NO{sup +} to MaPgb(II). Present results highlight the potential role of MaPgb in scavenging of reactive nitrogen and oxygen species.
- OSTI ID:
- 22224324
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 430, Issue 4; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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