Abstract
Microorganism's cycle exposure to reactive oxidants from internal metabolism and abiotic stress conditions, e.g. oxidative stress, salinity, drought, low temperature, high temperature, and high light. Synechocystis PCC6803 genomes typically encode different types of antioxidant scavenging enzymes including Peroxiredoxins (Prxs). There are five genes similar to Prxs were found inthe Synechocystis PCC 6803 genome. Based on sequence homology analysis of Synechocystis PCC 6803sll1621 gene, it is categorized into type II Prx (PrxII). The presumed amino acid sequence of Synechocystis PCC6803 PrxII protein exhibited identity about 44%-99% to other PrxII proteins from human, plants, algae, and other different cyanobacterial cells. In the last decade, the genetically controllable model organism E. coli has been introduced as a viable biotechnological model for genetically modified microorganisms. The Synechocystis PCC6803 sll1621 gene was overexpressed in pTYB21 expression vector and the resulting was named as pTY621/sll1621. The pTY621/sll1621 was overexpressed in Escherichia coli BL21 (DE3) host cell. The overexpressed protein of PrxII gave the recombinant E. coli cells the ability to survive under high concentrations of salinity stress, whereas the viability of wild type cells was completely inhibited at the same high concentrations of salinity stress. In conclusion, the present research documented the expressing of the sll1621 gene into E. coli cells. This result approved the absence of species barrier in relations to the function of Synechocystis PCC 6803 PrxII protein in different microorganism.