title: Synechocystis sp. PCC 6803 mutant lacking both photosystems exhibits strong carotenoid-induced quenching of phycobilisome fluorescence.
abstract: Blue light induced quenching in a Synechocystis sp. PCC 6803 strain lacking both photosystems is only related to allophycocyanin fluorescence. A fivefold decrease in the fluorescence level in two bands near 660 and 680 nm is attributed to different allophycocyanin forms in the phycobilisome core. Some low-heat sensitive component inactivated at 53°C is involved in the quenching process. Enormous allophycocyanin fluorescence in the absence of the photosystems reveals a dark stage in this quenching. Thus, we present evidence that light activation of the carotenoid-binding protein and formation of a quenching center within the phycobilisome core in vivo are discrete events in a multistep process.
authors.affiliation: AN Bakh Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia. rakhimberd@inbi.ras.ru
authors.forename: Marina G
authors.initials: MG
authors.lastname: Rakhimberdieva
authors.forename: Fedor I
authors.initials: FI
authors.lastname: Kuzminov
authors.forename: Irina V
authors.initials: IV
authors.lastname: Elanskaya
authors.forename: Navassard V
authors.initials: NV
authors.lastname: Karapetyan
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D002338:Carotenoids / Q000737:chemistry* / Q000378:metabolism; D005453:Fluorescence; D006358:Hot Temperature; D007700:Kinetics; D008027:Light; D009154:Mutation; D045331:Photosystem I Protein Complex / Q000235:genetics*; D045332:Photosystem II Protein Complex / Q000235:genetics*; D045524:Phycobilisomes / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects; D013050:Spectrometry, Fluorescence; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D045524:Phycobilisomes; D002338:Carotenoids