Inactivation of the extrinsic subunit of photosystem II, PsbU, in Synechococcus PCC 7942 results in elevated resistance to oxidative stress.
PsbU is a subunit of the extrinsic complex attached to the core of photosystem II. A PsbU-mutant of Synechococcus PCC 7942 was isolated based on its elevated resistance to externally applied oxidative stress. PsbU-mutant exhibits fast rates of degradation of the photosystem II core protein, D1, under sub-saturating as well as high-light conditions. While forward electron transfer is not affected, back electron flow is severely impaired in the mutant. We suggest that impairment of psbU results in production of reactive-oxygen-species, which trigger antioxidative mechanisms even under standard growth conditions. Accordingly, when challenged with external oxidative stress, these cells are more resistant than wild type cells.
Balint
Ido
I
Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
Bhattacharya
Jyotirmoy
J
Perelman
Alexander
A
Schatz
Daniella
D
Moskovitz
Yona
Y
Keren
Nir
N
Schwarz
Rakefet
R
D002470:Cell Survival / Q000187:drug effects; D005453:Fluorescence; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007700:Kinetics; D008027:Light; D009154:Mutation / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D010269:Paraquat / Q000494:pharmacology; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D021122:Protein Subunits / Q000378:metabolism*; D046940:Synechococcus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D013997:Time Factors
D045332:Photosystem II Protein Complex; D021122:Protein Subunits; D006861:Hydrogen Peroxide; D010269:Paraquat