Anti-oxidative stress system in cyanobacteria

Abstract

Thioredoxin is a ubiquitous, disulfide oxidoreductase with two redox active cysteines at the active center (-WCGPC-). In cyanobacteria and in chloroplasts of higher plants, thioredoxin is involved in light-dependent regulation of various enzymes. In addition, redox transfer via thioredoxin is important for an anti-oxidative stress system in the aerobic organisms. We had investigated the possible target proteins of thioredoxin of cyanobacteria in the whole cell lysate of Synechocystis sp. PCC6803 using immobilized mutant of thioredoxin and identified two peroxiredoxin like proteins as the major targets. In the present study, physiological significance of these proteins as anti-oxidative stress system in cyanobacteria was confirmed in vitro and in vivo.