A novel slr1050 protein is involved in the function of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803,A novel slr1050 protein is involved in the function of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803

Abstract

A transposon tagged mutant library was constructed in the Synechocystis sp. PCC 6803. A mutant selected was identified to have a disrupted slr1050, which encodes a putative membrane protein of 54.7 kDa. The slr1050::Tn5 mutant grew normally at low light (25 mmol m-2 s-1 or lower). However, the mutant showed a marked reduction in quantum yield and photosynthetic electron transport activity of photosystem II (PS II) with no apparent significant effects on the electron transport activity around photosystem I. Under high light (60 mmol m-2 s-1 or higher), the growth and chlorophyll a fluorescence profile of mutant showed its sensitivity to high light stress. Based on the electron transport activities, the lesion site of the photoinhibition seems to be PS II. These results led us to suggest that slr1050 protein is a membrane protein whose function is related with the electron donation to PS II.