title: Genus specific unusual carotenoids in purple bacteria, Phaeospirillum and Roseospira: structures and biosyntheses.
abstract: Phototrophic bacteria necessarily contain carotenoids for photosynthesis, and a few phototrophic purple bacteria accumulate unusual carotenoids. The carotenoids in the genera Phaeospirillum and Roseospira were identified using spectroscopic methods. All species of the genus Phaeospirillum contained characteristic polar carotenoids in addition to lycopene and hydroxylycopene (rhodopin); hydroxylycopene glucoside, dihydroxylycopene, and its mono- and/or diglucosides. From the structures of these carotenoids, their accumulation was suggested to be due to absence of CrtD (acyclic carotenoid C-3,4 desaturase) and to possession of glucosyltransferase. Species of the genus Roseospira have been reported to have unusual absorption spectra in acetone extract, and they were found to accumulate 3,4-didehydrorhodopin as a major carotenoid. This may be due to low activity of CrtF (acyclic 1-hydroxycarotenoid methyltransferase). The study concludes in identifying genus specific unusual carotenoids, which is probably due to characteristic nature of some carotenogenesis enzymes.
authors.affiliation: Department of Biology, Nippon Medical School, 297, Kosugi-cho 2, Nakahara, Kawasaki, 211-0063, Japan. takaichi@nms.ac.jp
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takaichi
authors.forename: Takashi
authors.initials: T
authors.lastname: Maoka
authors.forename: Ch
authors.initials: Ch
authors.lastname: Sasikala
authors.forename: Ch V
authors.initials: ChV
authors.lastname: Ramana
authors.forename: Keizo
authors.initials: K
authors.lastname: Shimada
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002338:Carotenoids / Q000096:biosynthesis* / Q000737:chemistry*; D015394:Molecular Structure; D012244:Rhodospirillaceae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D002338:Carotenoids