title: Inactivation of ycf33 results in an altered cyclic electron transport pathway around photosystem I in Synechocystis sp. PCC6803.
abstract: ycf33 encodes a small protein with a molecular mass of 7.5 kDa and is found from cyanobacteria to higher plants. A ycf33 deletion mutant was constructed in Synechocystis sp. PCC6803 and characterized. The mutant showed a higher phycobilisome/chlorophyll ratio than the wild type and a higher photosystem II/photosystem I fluorescence ratio measured at 77 K. Under photoautotrophic conditions, the growth rates were not much different from those of the wild type. Cyclic electron transport activities around photosystem I were not much different between the wild type and the mutant. However, the effects of diphenyleneiodonium, an inhibitor of flavoprotein, on cyclic electron transport in the mutant were different from those in the wild type; it was severely inhibited in the wild type but not much in the mutant. Together with the effects of nitrite, which accepts electrons from ferredoxin via nitrite reductase and those of HgCl2, it was suggested that the pathway of cyclic electron transport is altered in the mutant.
authors.affiliation: Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Garden City, Hyogo, 678-1297 Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Ohtsuka
authors.forename: Junko
authors.initials: J
authors.lastname: Oyabu
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kashino
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Satoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koike
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport; D008627:Mercuric Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D009861:Onium Compounds / Q000494:pharmacology; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D046939:Synechocystis / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D009861:Onium Compounds; D045331:Photosystem I Protein Complex; D008627:Mercuric Chloride; C007517:diphenyleneiodonium