title: A Dioxobilin-Type Fluorescent Chlorophyll Catabolite as a Transient Early Intermediate of the Dioxobilin-Branch of Chlorophyll Breakdown in Arabidopsis thaliana.
abstract: Chlorophyll breakdown in higher plants occurs by the so called "PaO/phyllobilin" path. It generates two major types of phyllobilins, the characteristic 1-formyl-19-oxobilins and the more recently discovered 1,19-dioxobilins. The hypothetical branching point at which the original 1-formyl-19-oxobilins are transformed into 1,19-dioxobilins is still elusive. Here, we clarify this hypothetical crucial transition on the basis of the identification of the first natural 1,19-dioxobilin-type fluorescent chlorophyll catabolite (DFCC). This transient chlorophyll breakdown intermediate was isolated from leaf extracts of Arabidopsis thaliana at an early stage of senescence. The fleetingly existent DFCC was then shown to represent the direct precursor of the major nonfluorescent 1,19-dioxobilin that accumulated in fully senescent leaves.
authors.affiliation: Institut für Organische Chemie und Centrum für Molekulare Biowissenschaften, Universität Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria).
authors.forename: Iris
authors.initials: I
authors.lastname: Süssenbacher
authors.affiliation: Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich (Switzerland).
authors.forename: Stefan
authors.initials: S
authors.lastname: Hörtensteiner
authors.affiliation: Institut für Organische Chemie und Centrum für Molekulare Biowissenschaften, Universität Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria). bernhard.kraeutler@uibk.ac.at.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kräutler
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000378:metabolism*; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D045725:Tetrapyrroles / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D045725:Tetrapyrroles; C000590876:dioxobilin; D002734:Chlorophyll
keywords: chlorophylls; isomerization; phyllobilin; structure elucidation; tetrapyrrole