Functional and structural changes in plant mitochondrial PrxII F caused by NO

Area of Science:

• Plant molecular biology
• Redox signaling
• Post-translational modifications

Background:

• Peroxiredoxins (Prxs) link reactive oxygen species (ROS) metabolism to redox signaling.
• Nitric oxide (NO) is a crucial signaling molecule in plants.
• S-Nitrosylation is a key post-translational modification mediating NO bioactivity.

Purpose of the Study:

• To investigate the effect of S-nitrosylation on pea mitochondrial PrxII F.
• To characterize the functional and structural changes in PrxII F upon S-nitrosylation.

Main Methods:

• Recombinant pea mitochondrial PrxII F was used.
• S-nitrosylation was induced using S-nitrosoglutathione (GSNO) and sodium nitroprusside dehydrate (SNP).
• S-Nitrosylation was confirmed using the biotin switch method and LC ESI-QTOF tandem MS analysis.
• Peroxidase and transnitrosylase activities were assessed, along with citrate synthase aggregation prevention.

Main Results:

• S-Nitrosylation of PrxII F was successfully demonstrated.
• S-nitrosylated PrxII F exhibited reduced peroxidase activity.
• S-nitrosylated PrxII F acquired transnitrosylase activity, preventing citrate synthase aggregation.
• A conformational change in PrxII F was observed upon S-nitrosylation, potentially enhancing protein-protein interactions.

Conclusions:

• S-Nitrosylation of PrxII F induces a dual function: reduced peroxidase activity and acquired transnitrosylase activity.
• This modification represents a novel regulatory mechanism for PrxII F by NO in plants.
• This finding enhances understanding of post-translational modifications in plant stress responses, particularly under salinity conditions where NO acts as a signaling molecule.