Turnover of the D1 protein and of Photosystem II in a Synechocystis 6803 mutant lacking Tyrz

Willem Vermaas, Cathy Madsen, Jiujiang Yu, Janine Visser, James Metz, Peter J. Nixon, Bruce Diner

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The Photosystem II reaction center is rapidly inactivated by light, particularly at higher light intensity. One of the possible factors causing this phenomenon is the oxidized primary donor, P680+, which may be harmful to Photosystem II because of its highly oxidizing nature. However, no direct evidence specificially implicating P680+ in photoinhibition has been obtained yet. To investigate whether P680+ is harmful to Photosystem II, turnover of the D1 protein and of the Photosystem II reaction center complex were measured in vivo in a mutant of the cyanobacterium Synechocystis sp. PCC 6803, in which the physiological donor to P680+, Tyrz, was genetically deleted. In this mutant, D1 degradation in the light is an order of magnitude faster than in wild type. The most straightforward explanation of this phenomenon is that accumulation of P680+ leads to an increased rate of turnover of the Photosystem II reaction center complex, which is compatible with the hypothesis of destructive oxidation by P680+ that is damaging to the Photosystem II complex.

Original languageEnglish (US)
Pages (from-to)99-104
Number of pages6
JournalPhotosynthesis research
Volume45
Issue number2
DOIs
StatePublished - Aug 1 1995

Keywords

  • chlorophyll radicals
  • cyanobacteria
  • photoinhibition
  • photosynthesis
  • protein degradation
  • thylakoids

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

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