Molecular recognition in the interaction of chloroplast 2-Cys peroxiredoxin with NADPH-thioredoxin reductase C (NTRC) and thioredoxin x

• Plant NTRC contains a NTR domain fused to a thioredoxin module and is an efficient reductant of 2-Cys peroxiredoxins.
• The interaction of NTRC and chloroplastic thioredoxin x with 2-Cys peroxiredoxin has been demonstrated both in vivo (by BiFC) and in vitro (by ITC).
• NTRC binds 2-Cys peroxiredoxin with higher affinity than thioredoxin x.
• Both the thioredoxin and NTR domains contribute to the interaction of NTRC with 2-Cys peroxiredoxin.
• The thioredoxin domain of NTRC prevents the interaction with thioredoxin x.

In addition to the standard NADPH thioredoxin reductases (NTRs), plants hold a plastidic NTR (NTRC), with a thioredoxin module fused at the C-terminus. NTRC is an efficient reductant of 2-Cys peroxiredoxins (2-Cys Prxs). The interaction of NTRC and chloroplastic thioredoxin x with 2-Cys Prxs has been confirmed in vivo, by bimolecular fluorescence complementation (BiFC) assays, and in vitro, by isothermal titration calorimetry (ITC) experiments. In comparison with thioredoxin x, NTRC interacts with 2-Cys Prx with higher affinity, both the thioredoxin and NTR domains of NTRC contributing significantly to this interaction, as demonstrated by using the NTR and thioredoxin modules of the enzyme expressed separately. The presence of the thioredoxin domain seems to prevent the interaction of NTRC with thioredoxin x.

Structured summary of protein interactionsNTRC and 2-Cys Prx B physically interact by bimolecular fluorescence complementation (View interaction)2-Cys Prx A and Trx x physically interact by bimolecular fluorescence complementation (View interaction)2-Cys Prx B and Trx x physically interact by bimolecular fluorescence complementation (View interaction)NTRC and 2-Cys Prx A physically interact by bimolecular fluorescence complementation (View interaction)2-Cys Prx and NTRC TrxM bind by isothermal titration calorimetry (View interaction)2-Cys Prx and NTRC bind by isothermal titration calorimetry (View interaction)2-Cys Prx and NTRC NtrM bind by isothermal titration calorimetry (View interaction)2-Cys Prx and Trx x bind by isothermal titration calorimetry (View interaction)NTRC TrxM and NTRC NtrM bind by isothermal titration calorimetry (View interaction)Trx x and NTRC NtrM bind by isothermal titration calorimetry (View interaction)NTRB and Trx h1 bind by isothermal titration calorimetry (View interaction)