A Cyanobacterium Synechocystis sp. PCC 6803 Glutaredoxin Gene (slr1562) Protects Escherichia coli against Abiotic Stresses

Problem statement: Glutaredoxins (GRXs) are ubiquitous small heat stable glutathione-dependent oxidoreductase enzymes that play a crucial role in plant development and response to oxidative stress. Approach: Cyanobacterium Synechocystis strain PCC 6803 contains two genes (slr1562 and ssr2061) encoding glutaredoxins. In the present investigation the slr1562 gene (grxC) was isolated and characterized. Results: The results revealed that the amino acid sequence deduced from GrxC protein share high identity with those of GRXs from other organisms and contain the consensus GRX family domain with a CPFC active site. Northern blotting analysis revealed that the expression of slr1562 gene could be induced by oxidative and salt stresses. Moreover, the protein GrxC was successfully overexpressed as a soluble fraction in Escherichia coli JM109. The over-expression of GrxC in Escherichia coli cells significantly increased resistance of cells to oxidative, drought and salt stresses. Conclusion/Recommendations: These results suggest that the slr1562 gene could play an important role in regulating abiotic tolerance against oxidative, drought and salt stresses in different organisms.