title: Carotenoid-induced quenching of the phycobilisome fluorescence in photosystem II-deficient mutant of Synechocystis sp.
abstract: Brief--10-second long--irradiation of a photosystem II-deficient mutant of cyanobacterium Synechocystis sp. PCC 6803 with intense blue or UV-B light causes an about 40% decrease of phycobilisome (PBS) fluorescence, slowly reversible in the dark. The registered action spectrum of PBS fluorescence quenching only shows bands at 500, 470 and 430 nm, typical of carotenoids, and an additional UV-B band; no peaks in the region of chlorophyll or PBS absorption have been found. We propose that quenching induced by carotenoids, possibly protein-bound or glycoside, reveals a new regulatory mechanism protecting photosynthetic apparatus of cyanobacteria against photodamage.
authors.affiliation: A.N. Bakh Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia. rakhimberd@inbi.ras.ru
authors.forename: Marina G
authors.initials: MG
authors.lastname: Rakhimberdieva
authors.forename: Igor N
authors.initials: IN
authors.lastname: Stadnichuk
authors.forename: Irina V
authors.initials: IV
authors.lastname: Elanskaya
authors.forename: Navassard V
authors.initials: NV
authors.lastname: Karapetyan
mesh_terms: D002338:Carotenoids / Q000494:pharmacology*; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D005453:Fluorescence; D009154:Mutation; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000502:physiology*; D045524:Phycobilisomes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D045524:Phycobilisomes; D002338:Carotenoids