Phycobilin/chlorophyll excitation equilibration upon carotenoid-induced non-photochemical fluorescence quenching in phycobilisomes of the cyanobacterium Synechocystis sp. PCC 6803

Marina G. Rakhimberdieva, Dmitrii V. Vavilin, Willem Vermaas, Irina V. Elanskaya, Navassard V. Karapetyan

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

To determine the mechanism of carotenoid-sensitized non-photochemical quenching in cyanobacteria, the kinetics of blue-light-induced quenching and fluorescence spectra were studied in the wild type and mutants of Synechocystis sp. PCC 6803 grown with or without iron. The blue-light-induced quenching was observed in the wild type as well as in mutants lacking PS II or IsiA confirming that neither IsiA nor PS II is required for carotenoid-triggered fluorescence quenching. Both fluorescence at 660 nm (originating from phycobilisomes) and at 681 nm (which, upon 440 nm excitation originates mostly from chlorophyll) was quenched. However, no blue-light-induced changes in the fluorescence yield were observed in the apcE- mutant that lacks phycobilisome attachment. The results are interpreted to indicate that interaction of the Slr1963-associated carotenoid with - presumably - allophycocyanin in the phycobilisome core is responsible for non-photochemical energy quenching, and that excitations on chlorophyll in the thylakoid equilibrate sufficiently with excitations on allophycocyanin in wild type to contribute to quenching of chlorophyll fluorescence.

Original languageEnglish (US)
Pages (from-to)757-765
Number of pages9
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1767
Issue number6
DOIs
StatePublished - Jun 2007

Keywords

  • Allophycocyanin
  • Carotenoid
  • Fluorescence quenching
  • IsiA protein
  • Photosystem II
  • Phycobilisome

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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