Abstract
Thioredoxin is a small (12-14 kDa) ubiquitous protein that has two reactive cysteins at the active site, Trp-Cys-Gly-Pro-Cys. The reduced form thioredoxin can reduce a disulphide bridge on target proteins. In cyanobacteria and in the chloroplasts of the higher plants, thioredoxins are involved in light-dependent regulation of enzymes. In addition, redox transfer via thioredoxin seems to be important as an anti-oxidant system in the aerobic organisms. The mutant thioredoxin, whose one cysteine at the active site is substituted to serine, can form a stable mixed-disulfide intermediate complex with a target protein. In this study we adopted the method to capture the possible target proteins for thioredoxins of cyanobacteria Synechocystis sp. PCC6803. Acquired proteins were identified by the analysis of the NH2-terminal sequence. Here, we found two peroxiredoxin like proteins in the acquired target proteins. The recombinant proteins were prepared in E. coli and their biochemical properties were investigated.
