RRC ID 30750
著者 Christ B, Süssenbacher I, Moser S, Bichsel N, Egert A, Müller T, Kräutler B, Hörtensteiner S.
タイトル Cytochrome P450 CYP89A9 is involved in the formation of major chlorophyll catabolites during leaf senescence in Arabidopsis.
ジャーナル Plant Cell
Abstract Nonfluorescent chlorophyll catabolites (NCCs) were described as products of chlorophyll breakdown in Arabidopsis thaliana. NCCs are formyloxobilin-type catabolites derived from chlorophyll by oxygenolytic opening of the chlorin macrocycle. These linear tetrapyrroles are generated from their fluorescent chlorophyll catabolite (FCC) precursors by a nonenzymatic isomerization inside the vacuole of senescing cells. Here, we identified a group of distinct dioxobilin-type chlorophyll catabolites (DCCs) as the major breakdown products in wild-type Arabidopsis, representing more than 90% of the chlorophyll of green leaves. The molecular constitution of the most abundant nonfluorescent DCC (NDCC), At-NDCC-1, was determined. We further identified cytochrome P450 monooxygenase CYP89A9 as being responsible for NDCC accumulation in wild-type Arabidopsis; cyp89a9 mutants that are deficient in CYP89A9 function were devoid of NDCCs but accumulated proportionally higher amounts of NCCs. CYP89A9 localized outside the chloroplasts, implying that FCCs occurring in the cytosol might be its natural substrate. Using recombinant CYP89A9, we confirm FCC specificity and show that fluorescent DCCs are the products of the CYP89A9 reaction. Fluorescent DCCs, formed by this enzyme, isomerize to the respective NDCCs in weakly acidic medium, as found in vacuoles. We conclude that CYP89A9 is involved in the formation of dioxobilin-type catabolites of chlorophyll in Arabidopsis.
巻・号 25(5)
ページ 1868-80
公開日 2013-5-1
DOI 10.1105/tpc.113.112151
PII tpc.113.112151
PMID 23723324
PMC PMC3694711
MeSH Arabidopsis / genetics* Arabidopsis / metabolism Arabidopsis / physiology Arabidopsis Proteins / genetics* Arabidopsis Proteins / metabolism Chlorophyll / chemistry Chlorophyll / metabolism* Chromatography, High Pressure Liquid Cytochrome P-450 Enzyme System / genetics* Cytochrome P-450 Enzyme System / metabolism Fluorescence Gene Expression Regulation, Plant Green Fluorescent Proteins / genetics Green Fluorescent Proteins / metabolism Mesophyll Cells / metabolism Microscopy, Confocal Molecular Structure Mutagenesis, Insertional Plant Leaves / genetics* Plant Leaves / metabolism Plant Leaves / physiology Plants, Genetically Modified Reverse Transcriptase Polymerase Chain Reaction Spectrometry, Mass, Electrospray Ionization Spectrophotometry
IF 9.618
引用数 67
WOS 分野 PLANT SCIENCES BIOCHEMISTRY & MOLECULAR BIOLOGY CELL BIOLOGY
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pda02355