PlumX Metrics
Embed PlumX Metrics

Investigating the photoprotective role of cytochrome b-559 in photosystem II in a mutant with altered ligation of the haem

Plant and Cell Physiology, ISSN: 1471-9053, Vol: 55, Issue: 7, Page: 1276-1285
2014
  • 20
    Citations
  • 0
    Usage
  • 30
    Captures
  • 0
    Mentions
  • 0
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

Article Description

Despite many years of study, the physiological role of cytochrome b-559 (Cyt b-559) within the photosystem II (PSII) complex still remains unclear. Here we describe the analysis of a mutant of the green alga Chlamydomonas reinhardtii in which the His ligand to the haem, provided by the alpha subunit, has been replaced by a Cys residue. The mutant is unable to grow photoautotrophically but can assemble oxygen-evolving PSII supercomplexes to 15-20% of the levels found in the wild-type control. Haem is still detected in the isolated PSII supercomplexes but at sub-stoichiometric levels consistent with weaker binding to the mutated cytochrome. Analysis of PSII activity in cells indicates slowed electron transfer in the mutant between plastoquinones Q and Q. We show that PSII activity in the mutant is more sensitive to chronic photoinhibition than the WT control because of two effects: a faster rate of damage and an impaired PSII repair cycle at the level of synthesis and/or incorporation of D1 into PSII. We also demonstrate that Cyt b-559 plays a role during the critical stage of assembling the Mn CaO cluster. Overall we conclude that Cyt b-559 optimises electron transfer on the acceptor side of PSII and plays physiologically important roles in the assembly, repair and maintenance of the complex. © 2014 The Author 2014.

Bibliographic Details

Hamilton, Mary L; Franco, Emanuel; Deák, Zsuzsanna; Schlodder, Eberhard; Vass, Imre; Nixon, Peter J

Oxford University Press (OUP)

Biochemistry, Genetics and Molecular Biology; Agricultural and Biological Sciences

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know