Defining the Photosystem II Repair Regulon in Synechocystis sp.PCC6803

Abstract

Light is the primary source of photosynthesis but one of draw backs of high light is the formation of reactive oxygen species. This potentially damages the D1 protein, this proteins forms the core of PSII. DI protein is capable of undergoing rapid turnover in high light and this turnover mechanism involves various factors such as FtsH proteases (slr0228) are involved in the removal of damaged D1, transcription regulators, including the sigma factors such as SigD that are involved in the regulation psbA genes under high light, and chaperones. The project was aimed to investigate the role of SigD in regulation of the hypothesized PSII repair regulon which includes psbA2, psbA3, ftsH(slr0228), ftsH(slr1604) and groEL-2. The findings suggest that ftsH(slr1604) also plays a role in the repair mechanism. But apart from these set of genes which seem to be coordinately regulated by SigD, there are other genes such as hli (high light inducible polypeptides) and genes that involved in the biosynthesis of chlorophyll and heme proteins. All these factors play an important role in the PSII repair mechanism.