The cyanobacterium Gloeobacter violaceus PCC 7421 uses bacterial-type phytoene desaturase in carotenoid biosynthesis.
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.
Tsuchiya
Tohru
T
Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan.
Takaichi
Shinichi
S
Misawa
Norihiko
N
Maoka
Takashi
T
Miyashita
Hideaki
H
Mimuro
Mamoru
M
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*
D002338:Carotenoids; D010088:Oxidoreductases; C022398:phytoene dehydrogenase