Electron transport routes in whole cells of Synechocystis sp. Strain PCC 6803: The role of the cytochrome bd-type oxidase

Stephan Berry, Dirk Schneider, Willem Vermaas, Matthias Rögner

Research output: Contribution to journalArticle

77 Scopus citations


The plastoquinone pool is the central switching point of both respiratory and photosynthetic electron transport in cyanobacteria. Its redox state can be monitored noninvasively in whole cells using chlorophyll fluorescence induction, avoiding possible artifacts associated with thylakoid membrane preparations. This method was applied to cells of Synechocystis sp. PCC 6803 to study respiratory reactions involving the plastoquinone pool. The role of the respiratory oxidases known from the genomic sequence of Synechocystis sp. PCC 6803 was investigated by a combined strategy using inhibitors and deletion strains that lack one or more of these oxidases. The putative quinol oxidase of the cytochrome bd-type was shown to participate in electron transport in thylakoid membranes. The activity of this enzyme in thylakoids was strongly dependent on culture conditions; it was increased under conditions where the activity of the cytochrome b6f complex alone may be insufficient for preventing over-reduction of the PQ pool. In contrast, no indication of quinol oxidase activity in thylakoids was found for a second alternative oxidase encoded by the call genes.

Original languageEnglish (US)
Pages (from-to)3422-3429
Number of pages8
Issue number10
StatePublished - Mar 12 2002


ASJC Scopus subject areas

  • Biochemistry

Cite this