Analysis of the proteins targeted by CDSP32, a plastidic thioredoxin participating in oxidative stress responses.

The chloroplastic drought-induced stress protein of 32 kDa (CDSP32) is a thioredoxin induced by environmental stress conditions. To gain insight into the function of CDSP32, we applied two strategies to analyze its targets. First, using affinity chromatography with an immobilized CDSP32 active site mutant, we identified six plastidic targets of CDSP32.

Potato plants lacking the CDSP32 plastidic thioredoxin exhibit overoxidation of the BAS1 2-cysteine peroxiredoxin and increased lipid Peroxidation in thylakoids under photooxidative stress.

The CDSP32 protein (chloroplastic drought-induced stress protein of 32 kD) is a thioredoxin participating in the defense against oxidative damage. We recently have identified in vitro the BAS1 2-Cys peroxiredoxin, a peroxide-detoxifying enzyme, as a target for CDSP32. Here, we report the characterization under stress conditions of transgenic potato (Solanum tuberosum) plants lacking CDSP32 with regard to the BAS1 redox state and the level of lipid peroxidation.

The plastidic 2-cysteine peroxiredoxin is a target for a thioredoxin involved in the protection of the photosynthetic apparatus against oxidative damage.

The chloroplastic drought-induced stress protein of 32 kD (CDSP32) is composed of two thioredoxin modules and is induced by environmental and oxidative stress conditions. We investigated whether the plastidic protein BAS1, which is related to eubacterial 2-Cys peroxiredoxin, is a target for CDSP32. Using a CDSP32 active-site mutant, we showed that the BAS1 and CDSP32 proteins form a mixed disulfide complex in vitro.