Evidence that cytochrome b559 mediates the oxidation of reduced plastoquinone in the dark

Natallia Bondarava, Luca De Pascalis, Salim Al-Babili, Charilaos Goussias, Jochen R. Golecki, Peter Beyer, Ralph Bock, Anja Krieger-Liszkay*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

The function of cytochrome b559 in photosystem II (PSII) was investigated using a mutant created in tobacco in which the conserved phenylalanine at position 26 in the β-subunit (PsbF) was changed to serine (Bock, R., Kössel, H., and Maliga, P. (1994) EMBO J. 13, 4623-4628). The mutant grew photoautotrophically, but the amount of PSII was reduced and the ultrastructure of the chloroplast was dramatically altered. Very few grana stacks were formed in the mutant. Although isolated PSII-enriched membrane fragments showed low PSII activity, electron paramagnetic resonance indicated the presence of functional PSII. Difference absorption spectra showed that the cytochrome b559 contained heme. The plastoquinone pool was largely reduced in dark-adapted leaves of the mutant, based on chlorophyll fluorescence and thermoluminescence measurements. We therefore propose that cytochrome b559 plays an important role in PSII by keeping the plastoquinone pool and thereby the acceptor side of PSII oxidized in the dark. Structural alterations as induced by the single Phe → Ser point mutation in the transmembrane domain of PsbF evidently inhibit this function.

Original languageEnglish (US)
Pages (from-to)13554-13560
Number of pages7
JournalJournal of Biological Chemistry
Volume278
Issue number15
DOIs
StatePublished - Apr 11 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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