title: An ORF323 with homology to crtE, specifying prephytoene pyrophosphate dehydrogenase, is encoded by cyanelle DNA in the eukaryotic alga Cyanophora paradoxa.
abstract: Carotenoids are essential constituents of the light-harvesting and light-protective systems of photosynthetic organisms. The biochemistry of carotenoid biosynthesis in eukaryotes is known, whereas evidence for the genes specifying this biosynthetic pathway is scant. We report here the nucleotide sequence and expression of a gene likely encoding crtE (prephytoene pyrophosphate dehydrogenase). The reaction product of this enzyme is phytoene, a C40 carotenoid precursor common to all organisms. The gene is found in the cyanelle (plastid) DNA of an eukaryotic alga, Cyanophora paradoxa. The expression into protein of cyanelle crtE has been demonstrated in vitro. The identity and similarity scores of CrtE from cyanelles with the corresponding protein from the photosynthetic bacterium Rhodobacter capsulatus are 28.6 and 68.5%, respectively.
authors.affiliation: Department of Biochemistry, University of Arizona, Tucson 85721.
authors.forename: C B
authors.initials: CB
authors.lastname: Michalowski
authors.forename: W
authors.initials: W
authors.lastname: Löffelhardt
authors.forename: H J
authors.initials: HJ
authors.lastname: Bohnert
mesh_terms: D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D056890:Eukaryota / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D015388:Organelles / Q000201:enzymology*; D010088:Oxidoreductases / Q000235:genetics*; D014176:Protein Biosynthesis; D012313:RNA / Q000032:analysis; D016354:Rhodobacter capsulatus / Q000201:enzymology; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
chemical_list: D012313:RNA; D004247:DNA; D010088:Oxidoreductases; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase