title: The cyanobacterium Gloeobacter violaceus PCC 7421 uses bacterial-type phytoene desaturase in carotenoid biosynthesis.
abstract: Carotenoid composition and its biosynthetic pathway in the cyanobacterium Gloeobacter violaceus PCC 7421 were investigated. beta-Carotene and (2S,2'S)-oscillol 2,2'-di(alpha-L-fucoside), and echinenone were major and minor carotenoids, respectively. We identified two unique genes for carotenoid biosynthesis using in vivo functional complementation experiments. In Gloeobacter, a bacterial-type phytoene desaturase (CrtI), rather than plant-type desaturases (CrtP and CrtQ), produced lycopene. This is the first demonstration of an oxygenic photosynthetic organism utilizing bacterial-type phytoene desaturase. We also revealed that echinenone synthesis is catalyzed by CrtW rather than CrtO. These findings indicated that Gloeobacter retains ancestral properties of carotenoid biosynthesis.
authors.affiliation: Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takaichi
authors.forename: Norihiko
authors.initials: N
authors.lastname: Misawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Maoka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyashita
authors.forename: Mamoru
authors.initials: M
authors.lastname: Mimuro
mesh_terms: D002338:Carotenoids / Q000096:biosynthesis*; D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D010088:Oxidoreductases / Q000378:metabolism*
chemical_list: D002338:Carotenoids; D010088:Oxidoreductases; C022398:phytoene dehydrogenase