A1 Refereed original research article in a scientific journal
Protection by alpha-tocopherol of the repair of photosystem II during photoinhibition in Synechocystis sp PCC 6803
Authors: Inoue S, Ejima K, Iwai E, Hayashi H, Appel J, Tyystjarvi E, Murata N, Nishiyama Y
Publisher: ELSEVIER SCIENCE BV
Publication year: 2011
Journal: BBA - Bioenergetics
Journal name in source: BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
Journal acronym: BBA-BIOENERGETICS
Number in series: 2
Volume: 1807
Issue: 2
First page : 236
Last page: 241
Number of pages: 6
ISSN: 0005-2728
DOI: https://doi.org/10.1016/j.bbabio.2010.11.003
Abstract
alpha-Tocopherol is a lipophilic antioxidant that is an efficient scavenger of singlet oxygen. We investigated the role of alpha-tocopherol in the protection of photosystem II (PSII) from photoinhibition using a mutant of the cyanobacterium Synechocystis sp. PCC 6803 that is deficient in the biosynthesis of a-tocopherol. The activity of PSII in mutant cells was more sensitive to inactivation by strong light than that in wild-type cells, indicating that lack of alpha-tocopherol enhances the extent of photoinhibition. However, the rate of photodamage to PSII, as measured in the presence of chloramphenicol, which blocks the repair of PSII, did not differ between the two lines of cells. By contrast, the repair of PSII from photodamage was suppressed in mutant cells. Addition of alpha-tocopherol to cultures of mutant cells returned the extent of photoinhibition to that in wild-type cells, without any effect on photodamage. The synthesis de novo of various proteins, including the D1 protein that plays a central role in the repair of PSII, was suppressed in mutant cells under strong light. These observations suggest that alpha-tocopherol promotes the repair of photodamaged PSII by protecting the synthesis de novo of the proteins that are required for recovery from inhibition by singlet oxygen. (C) 2010 Elsevier B.V. All rights reserved.
alpha-Tocopherol is a lipophilic antioxidant that is an efficient scavenger of singlet oxygen. We investigated the role of alpha-tocopherol in the protection of photosystem II (PSII) from photoinhibition using a mutant of the cyanobacterium Synechocystis sp. PCC 6803 that is deficient in the biosynthesis of a-tocopherol. The activity of PSII in mutant cells was more sensitive to inactivation by strong light than that in wild-type cells, indicating that lack of alpha-tocopherol enhances the extent of photoinhibition. However, the rate of photodamage to PSII, as measured in the presence of chloramphenicol, which blocks the repair of PSII, did not differ between the two lines of cells. By contrast, the repair of PSII from photodamage was suppressed in mutant cells. Addition of alpha-tocopherol to cultures of mutant cells returned the extent of photoinhibition to that in wild-type cells, without any effect on photodamage. The synthesis de novo of various proteins, including the D1 protein that plays a central role in the repair of PSII, was suppressed in mutant cells under strong light. These observations suggest that alpha-tocopherol promotes the repair of photodamaged PSII by protecting the synthesis de novo of the proteins that are required for recovery from inhibition by singlet oxygen. (C) 2010 Elsevier B.V. All rights reserved.
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