title: Functional and structural changes in plant mitochondrial PrxII F caused by NO.
abstract: Peroxiredoxins (Prxs) have emerged as important factors linking reactive oxygen species (ROS) metabolism to redox-dependent signaling events. Together with ROS, nitric oxide (NO) is a free radical product of the cell metabolism that is essential in the signal transduction. S-Nitrosylation is emerging as a fundamental protein modification for the transduction of NO bioactivity. Using recombinant pea mitochondrial PsPrxII F (PrxII F), the effect of S-nitrosoglutathione (GSNO) and sodium nitroprusside dehydrate (SNP), which are known to mediate protein S-nitrosylation processes, was studied. S-Nitrosylation of the PrxII F was demonstrated using the biotin switch method and LC ESI-QTOF tandem MS analysis. S-nitrosylated PrxII F decreased its peroxidase activity and acquired a new transnitrosylase activity, preventing the thermal aggregation of citrate synthase (CS). For the first time, we demonstrate the dual function for PrxII F as peroxidase and transnitrosylase. This switch was accompanied by a conformational change of the protein that could favor the protein-protein interaction CS-PrxII F. The observed in vivo S-nitrosylation of PrxII F could probably function as a protective mechanism under oxidative and nitrosative stress, such as occurs under salinity. We conclude that we are dealing with a novel regulatory mechanism for this protein by NO.
  
  
  CONCLUSIONS
  S-Nitrosylation is a post-translational modification that is increasingly viewed as fundamental for the signal transduction role of NO in plants. This study demonstrates that S-nitrosylation of the mitochondrial peroxiredoxin PrxII F induces a conformational change in the protein and provokes a reduction in its peroxidase activity, while acquiring a novel function as transnitrosylase. The implication of this mechanism will increase our understanding of the role of posttranslational modifications in the protein function in plants under stress situations such as salinity, in which NO could act as signaling molecule.
authors: CEBAS-CSIC, Department of Stress Biology and Plant Pathology, E-30100 Murcia, Spain. Electronic address: dcamejo@cebas.csic.es.
authors: Daymi
authors: D
authors: Camejo
authors: CEBAS-CSIC, Department of Stress Biology and Plant Pathology, E-30100 Murcia, Spain. Electronic address: amortiz@cebas.csic.es.
authors: Ana
authors: A
authors: Ortiz-Espín
authors: EEZ-CSIC, Department of Biochemistry, Cellular and Molecular Biology of Plants, E-18080 Granada, Spain. Electronic address: jjlazaro@eez.csic.es.
authors: Juan J
authors: JJ
authors: Lázaro
authors: EEZ-CSIC, Department of Biochemistry, Cellular and Molecular Biology of Plants, E-18080 Granada, Spain. Electronic address: maria.romero@eez.csic.es.
authors: María C
authors: MC
authors: Romero-Puertas
authors: EEZ-CSIC, Department of Biochemistry, Cellular and Molecular Biology of Plants, E-18080 Granada, Spain. Electronic address: alfonso.lazaro@eez.csic.es.
authors: Alfonso
authors: A
authors: Lázaro-Payo
authors: CEBAS-CSIC, Department of Stress Biology and Plant Pathology, E-30100 Murcia, Spain. Electronic address: fsevilla@cebas.csic.es.
authors: Francisca
authors: F
authors: Sevilla
authors: CEBAS-CSIC, Department of Stress Biology and Plant Pathology, E-30100 Murcia, Spain. Electronic address: ajimenez@cebas.csic.es.
authors: Ana
authors: A
authors: Jiménez
mesh_terms: D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D018532:Pisum sativum / Q000201:enzymology*; D054464:Peroxiredoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins
chemical_list: D024101:Mitochondrial Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D009569:Nitric Oxide; D054464:Peroxiredoxins
keywords: Mitochondrial PsPrxII F oligomerization; Peroxidase; S-Nitrosylation; Salinity; Transnitrosylase