Chlorophyll Breakdown in Senescent Chloroplasts (Cleavage of Pheophorbide a in Two Enzymic Steps)

Rodoni, Simona; Mühlecker, Walter; Anderl, M.; Kräutler, Bernhard; Moser, Daniel; Thomas, Howard; Matile, Philippe; Hörtensteiner, Stefan

doi:10.1104/pp.115.2.669

Cited by 161 publications

(153 citation statements)

References 27 publications

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“…However, the subchloroplast location of respective reactions remained largely unclear until recently, in particular because of the inconsistency with regard to the presence or absence of transmembrane domains in these proteins. Thus, for example, PAO is an integral membrane protein with two predicted transmembrane domains ( Figure 5A) (Sakuraba et al, 2012), while RCCR, with which it physically interacts during catalysis (Rodoni et al, 1997;Pruzinská et al, 2007), is a soluble protein (Wüthrich et al, 2000). Recently, based on protein interaction studies, we proposed the model that all chloroplastlocated chlorophyll catabolic enzymes form a highly dynamic multiprotein complex at the thylakoid membrane with interaction with light harvesting complex II proteins (Sakuraba et al, 2012).…”

Section: Spatial Distribution Of Chlorophyll Catabolic Enzymes Withinmentioning

confidence: 99%

“…For this, we used epi-pFCC that we produced from pheophorbide a in a well established in vitro system using bell pepper chromoplasts (Christ et al, 2012). On reverse-phase HPLC, epi-pFCC has a longer retention time than pFCC ( Figure 2C) (Rodoni et al, 1997), but the fragmentation behavior in tandem MS experiments with a stable ring D was identical to that of pFCC (Supplemental Figure 1A). When incubating at pH 5, epi-pFCC isomerized to a more polar compound (Supplemental Figure 1B), which when analyzed by tandem MS fragmented as a typical NCC (Christ et al, 2016), i.e., with high probability of ring D loss (Supplemental Figure 1A), confirming the identity of the catabolites isolated from senescent Arabidopsis chloroplasts as FCCs, specifically as pFCC and hydroxy-pFCC, which solely differ by the attachment in the latter of an additional oxygen atom at ring A, likely at the C3 2 ethyl side chain.…”

Section: Hydroxy-pfcc Is Present In Gerontoplasts Of Arabidopsismentioning

confidence: 99%

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A Role for TIC55 as a Hydroxylase of Phyllobilins, the Products of Chlorophyll Breakdown during Plant Senescence

et al. 2016

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ORCID IDs: 0000-0002-0044-0490 (M.H.); 0000-0002-7598-3609 (S.A.) Chlorophyll degradation is the most obvious hallmark of leaf senescence. Phyllobilins, linear tetrapyrroles that are derived from opening of the chlorin macrocycle by the Rieske-type oxygenase PHEOPHORBIDE a OXYGENASE (PAO), are the end products of chlorophyll degradation. Phyllobilins carry defined modifications at several peripheral positions within the tetrapyrrole backbone. While most of these modifications are species-specific, hydroxylation at the C3 2 position is commonly found in all species analyzed to date. We demonstrate that this hydroxylation occurs in senescent chloroplasts of Arabidopsis thaliana. Using bell pepper (Capsicum annuum) chromoplasts, we establish that phyllobilin hydroxylation is catalyzed by a membrane-bound, molecular oxygen-dependent, and ferredoxin-dependent activity. As these features resemble the requirements of PAO, we considered membrane-bound Rieske-type oxygenases as potential candidates. Analysis of mutants of the two Arabidopsis Rieske-type oxygenases (besides PAO) uncovered that phyllobilin hydroxylation depends on TRANSLOCON AT THE INNER CHLOROPLAST ENVELOPE55 (TIC55). Our work demonstrates a catalytic activity for TIC55, which in the past has been considered as a redox sensor of protein import into plastids. Given the wide evolutionary distribution of both PAO and TIC55, we consider that chlorophyll degradation likely coevolved with land plants.

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Section: Spatial Distribution Of Chlorophyll Catabolic Enzymes Withinmentioning

confidence: 99%

Section: Hydroxy-pfcc Is Present In Gerontoplasts Of Arabidopsismentioning

confidence: 99%

A Role for TIC55 as a Hydroxylase of Phyllobilins, the Products of Chlorophyll Breakdown during Plant Senescence

et al. 2016

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“…The product of this reaction, red chlorophyll catabolite (RCC), is then reduced to pFCC in a regio-and stereoselective manner catalyzed by RCC reductase (RCCR) (Pruž inská et al, 2007). Biochemical and two-hybrid experiments indicated interaction between PAO and RCCR as well as metabolic channeling of RCC (Rodoni et al, 1997;Pruž inská et al, 2007). PAO activity provides the structural basis for all further breakdown products (i.e., RCCs, FCCs, and NCCs).…”

Section: Introductionmentioning

confidence: 99%

STAY-GREEN and Chlorophyll Catabolic Enzymes Interact at Light-Harvesting Complex II for Chlorophyll Detoxification during Leaf Senescence in Arabidopsis

et al. 2012

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During leaf senescence, plants degrade chlorophyll to colorless linear tetrapyrroles that are stored in the vacuole of senescing cells. The early steps of chlorophyll breakdown occur in plastids. To date, five chlorophyll catabolic enzymes (CCEs), NONYELLOW COLORING1 (NYC1), NYC1-LIKE, pheophytinase, pheophorbide a oxygenase (PAO), and red chlorophyll catabolite reductase, have been identified; these enzymes catalyze the stepwise degradation of chlorophyll to a fluorescent intermediate, pFCC, which is then exported from the plastid. In addition, STAY-GREEN (SGR), Mendel's green cotyledon gene encoding a chloroplast protein, is required for the initiation of chlorophyll breakdown in plastids. Senescence-induced SGR binds to light-harvesting complex II (LHCII), but its exact role remains elusive. Here, we show that all five CCEs also specifically interact with LHCII. In addition, SGR and CCEs interact directly or indirectly with each other at LHCII, and SGR is essential for recruiting CCEs in senescing chloroplasts. PAO, which had been attributed to the inner envelope, is found to localize in the thylakoid membrane. These data indicate a predominant role for the SGR-CCE-LHCII protein interaction in the breakdown of LHCII-located chlorophyll, likely to allow metabolic channeling of phototoxic chlorophyll breakdown intermediates upstream of nontoxic pFCC.

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“…The pathway starts with the removal of phytol and Mg by chlorophyllase (Willstä tter and Stoll, 1913) and metalchelating substance (Suzuki et al, 2005), respectively, before the porphyrin ring of the resulting intermediate, pheophorbide (pheide), is oxygenolytically opened by pheide a oxygenase (PAO) (Hö rtensteiner et al, 1998). The product of this reaction is red chlorophyll catabolite, which, without release from PAO, is site-specifically reduced by red chlorophyll catabolite reductase to yield the primary fluorescent chlorophyll catabolite (FCC), pFCC Rodoni et al, 1997). After export from the chloroplast (Matile et al, 1992), pFCC is modified by reactions reminiscent of detoxification processes widely occurring in plants (Kreuz et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Pheophytin Pheophorbide Hydrolase (Pheophytinase) Is Involved in Chlorophyll Breakdown during Leaf Senescence in Arabidopsis

et al. 2009

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During leaf senescence, chlorophyll is removed from thylakoid membranes and converted in a multistep pathway to colorless breakdown products that are stored in vacuoles. Dephytylation, an early step of this pathway, increases water solubility of the breakdown products. It is widely accepted that chlorophyll is converted into pheophorbide via chlorophyllide. However, chlorophyllase, which converts chlorophyll to chlorophyllide, was found not to be essential for dephytylation in Arabidopsis thaliana. Here, we identify pheophytinase (PPH), a chloroplast-located and senescence-induced hydrolase widely distributed in algae and land plants. In vitro, Arabidopsis PPH specifically dephytylates the Mg-free chlorophyll pigment, pheophytin (phein), yielding pheophorbide. An Arabidopsis mutant deficient in PPH (pph-1) is unable to degrade chlorophyll during senescence and therefore exhibits a stay-green phenotype. Furthermore, pph-1 accumulates phein during senescence. Therefore, PPH is an important component of the chlorophyll breakdown machinery of senescent leaves, and we propose that the sequence of early chlorophyll catabolic reactions be revised. Removal of Mg most likely precedes dephytylation, resulting in the following order of early breakdown intermediates: chlorophyll / pheophytin / pheophorbide. Chlorophyllide, the last precursor of chlorophyll biosynthesis, is most likely not an intermediate of breakdown. Thus, chlorophyll anabolic and catabolic reactions are metabolically separated.

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Chlorophyll Breakdown in Senescent Chloroplasts (Cleavage of Pheophorbide a in Two Enzymic Steps)

Cited by 161 publications

References 27 publications

A Role for TIC55 as a Hydroxylase of Phyllobilins, the Products of Chlorophyll Breakdown during Plant Senescence

A Role for TIC55 as a Hydroxylase of Phyllobilins, the Products of Chlorophyll Breakdown during Plant Senescence

STAY-GREEN and Chlorophyll Catabolic Enzymes Interact at Light-Harvesting Complex II for Chlorophyll Detoxification during Leaf Senescence in Arabidopsis

Pheophytin Pheophorbide Hydrolase (Pheophytinase) Is Involved in Chlorophyll Breakdown during Leaf Senescence in Arabidopsis

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