title: Light-independent and light-dependent protochlorophyllide-reducing activities and two distinct NADPH-protochlorophyllide oxidoreductase polypeptides in mountain pine (Pinus mugo).
abstract: Lower plants and gymnosperms synthesize chlorophyll and develop photosynthetically competent chloroplasts even when grown in the dark. In cell-free extracts of pine (Pinus mugo, Turra, ssp. mugo) seedlings, light-independent and light-dependent protochlorophyllide-reducing activities are present. Two distinct NADPH-protochlorophyllide-oxidoreductase (POR) polypeptides can be detected immunologically with an antiserum raised against the POR of barley. The subcellular localization and amounts of the two POR polypeptides are differentially affected by light: one of them is predominantly present in prolamellar bodies of etiochloroplasts and its abundance rapidly declines once the pine seedlings are exposed to light; the other is found in thylakoid membranes and its amount does not change during illumination of dark-grown seedlings. Two types of cDNA sequences are identified that encode two distinct POR polypeptides in pine. The relevance of these POR polypeptides for the two chlorophyll biosynthetic pathways active in gymnosperms is discussed.
authors.affiliation: Swiss Federal Institute of Technology (ETH), Abteilung Pflanzengenetik, ETH-Zentrum, Zürich.
authors.forename: C
authors.initials: C
authors.lastname: Forreiter
authors.forename: K
authors.initials: K
authors.lastname: Apel
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002734:Chlorophyll / Q000096:biosynthesis / Q000235:genetics; D004247:DNA; D001467:Hordeum / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D007150:Immunohistochemistry; D008027:Light; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000032:analysis* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010455:Peptides / Q000032:analysis / Q000235:genetics; D010936:Plant Extracts / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism / Q000528:radiation effects; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000201:enzymology* / Q000528:radiation effects
chemical_list: D010455:Peptides; D010936:Plant Extracts; D010940:Plant Proteins; D012333:RNA, Messenger; D002734:Chlorophyll; D004247:DNA; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase