RRC ID 4066
著者 Pruzinská A, Tanner G, Anders I, Roca M, Hörtensteiner S.
タイトル Chlorophyll breakdown: pheophorbide a oxygenase is a Rieske-type iron-sulfur protein, encoded by the accelerated cell death 1 gene.
ジャーナル Proc Natl Acad Sci U S A
Abstract Chlorophyll (chl) breakdown during senescence is an integral part of plant development and leads to the accumulation of colorless catabolites. The loss of green pigment is due to an oxygenolytic opening of the porphyrin macrocycle of pheophorbide (pheide) a followed by a reduction to yield a fluorescent chl catabolite. This step is comprised of the interaction of two enzymes, pheide a oxygenase (PaO) and red chl catabolite reductase. PaO activity is found only during senescence, hence PaO seems to be a key regulator of chl catabolism. Whereas red chl catabolite reductase has been cloned, the nature of PaO has remained elusive. Here we report on the identification of the PaO gene of Arabidopsis thaliana (AtPaO). AtPaO is a Rieske-type iron-sulfur cluster-containing enzyme that is identical to Arabidopsis accelerated cell death 1 and homologous to lethal leaf spot 1 (LLS1) of maize. Biochemical properties of recombinant AtPaO were identical to PaO isolated from a natural source. Production of fluorescent chl catabolite-1 required ferredoxin as an electron source and both substrates, pheide a and molecular oxygen. By using a maize lls1 mutant, the in vivo function of PaO, i.e., degradation of pheide a during senescence, could be confirmed. Thus, lls1 leaves stayed green during dark incubation and accumulated pheide a that caused a light-dependent lesion mimic phenotype. Whereas proteins were degraded similarly in wild type and lls1, a chl-binding protein was selectively retained in the mutant. PaO expression correlated positively with senescence, but the enzyme appeared to be post-translationally regulated as well.
巻・号 100(25)
ページ 15259-64
公開日 2003-12-9
DOI 10.1073/pnas.2036571100
PII 2036571100
PMID 14657372
PMC PMC299977
MeSH Apoptosis Regulatory Proteins Arabidopsis / genetics Arabidopsis Proteins / chemistry Cell Death Cellular Senescence Chlorophyll / analogs & derivatives* Chlorophyll / chemistry* DNA, Complementary / metabolism Dose-Response Relationship, Drug Electron Transport Complex III / chemistry* Electrons Ferredoxins / chemistry Iron-Sulfur Proteins / chemistry* Models, Chemical Mutation Oxidoreductases / chemistry Oxygen / metabolism Oxygenases / chemistry* Phenotype Plant Leaves / metabolism Protein Biosynthesis Recombinant Proteins / metabolism Reverse Transcriptase Polymerase Chain Reaction Time Factors Zea mays / chemistry Zea mays / genetics
IF 9.412
引用数 279
WOS 分野 PLANT SCIENCES
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pda07874 pda06002