Abstract
Thioredoxin (Trx) is a ubiquitous protein, which supplies the reducing equivalents to the target proteins to maintain the redox conditions in the cell. In general, cyanobacterium has two Trx reducing pathways; NADPH-Trx reductase (NTR) pathway and Fd-Trx reductase pathway. Based on the analyses of the NTR and FTR disruptants of Synechocystis sp. PCC6803, NTR was clarified to be critical for the antioxidant system, though the terminal proteins of two Trx reductase pathways were not known yet (Hishiya et al. 2008). In this study, we compared the oxidized proteins in the wild cells with those in the Trx reductase disruptants by 2D-electrophoresis following the fluorescence labeling of the oxidized proteins. Consequently, we successfully detected several proteins observed especially in the mutant cells. In addition, difference of the protein expression level in the mutant cells under the oxidized conditions was investigated by conventional 2D-electrophoresis. Based on these studies, the difference of two Trx reductase pathways in cyanobacteria is discussed.
