Publications

• Chlorophyll degradation during senescence.

  Hortensteiner S.

  The catabolic pathway of chlorophyll (Chl) during senescence and fruit ripening leads to the accumulation of colorless breakdown products (NCCs). This review updates an earlier review on Chl breakdown published here in 1999 ( 69 ). It summarizes recent advances in the biochemical reactions of the ... >> More

  The catabolic pathway of chlorophyll (Chl) during senescence and fruit ripening leads to the accumulation of colorless breakdown products (NCCs). This review updates an earlier review on Chl breakdown published here in 1999 ( 69 ). It summarizes recent advances in the biochemical reactions of the pathway and describes the characterization of new NCCs and their formation inside the vacuole. Furthermore, I focus on the recent molecular identification of three chl catabolic enzymes, chlorophyllase, pheophorbide a oxygenase (PAO), and red Chl catabolite reductase (RCCR). The analysis of Chl catabolic mutants demonstrates the importance of Chl breakdown for plant development and survival. Mutants defective in PAO or RCCR develop a lesion mimic phenotype, due to the accumulation of breakdown intermediates. Thus, Chl breakdown is a prerequisite to detoxify the potentially phototoxic pigment within the vacuoles in order to permit the remobilization of nitrogen from Chl-binding proteins to proceed during senescence. << Less

  Annu Rev Plant Biol 57:55-77(2006) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.

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

  Rodoni S., Muhlecker W., Anderl M., Krautler B., Moser D., Thomas H., Matile P., Hortensteiner S.

  The cleavage of pheophorbide (Pheide) a into primary fluoescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures wer ... >> More

  The cleavage of pheophorbide (Pheide) a into primary fluoescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures were supplemented with ferredoxin (Fd). pFCC production in detergent-solubilized membranes was dependent on the presence of an Fd-reducing system. Pheide a cleavage required the action of two proteins, Pheide a oxygenase and a stroma protein. In the absence of stroma protein, Pheide a oxygenase converted Pheide a into a red Chl catabolite (RCC), the presumptive intermediary product of Pheide a cleavage. Incubation of the stroma protein (RCC reductase) together with chemically synthesized RCC resulted in the production of three different FCCs. Two of these catabolites were identical to the pFCCs from canola or barley (Hordeum vulgare) (pFCC-1) and sweet pepper (Capsicum annuum) (pFCC-2), respectively. Thus, the conversion of Pheide a to pFCC could be demonstrated to proceed in two consecutive steps, and both reactions depended on reduced Fd as the source of electrons. The function of Fd in Chl breakdown in vivo is corroborated by the marked retention of this protein until the late stages of senescence, as demonstrated by immunoblotting. << Less

  Plant Physiol 115:669-676(1997) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Partial purification and characterization of red chlorophyll catabolite reductase, a stroma protein involved in chlorophyll breakdown.

  Rodoni S., Vicentini F., Schellenberg M., Matile P., Hortensteiner S.

  Red chlorophyll (Chl) catabolite (RCC) reductase, which catalyzes the reaction of an intermediary Chl catabolite (RCC) in the two-step cleavage reaction of pheophorbide (Pheide) a into primary fluorescent catabolites (pFCCs) during Chl breakdown, was characterized and partially purified. RCC reduc ... >> More

  Red chlorophyll (Chl) catabolite (RCC) reductase, which catalyzes the reaction of an intermediary Chl catabolite (RCC) in the two-step cleavage reaction of pheophorbide (Pheide) a into primary fluorescent catabolites (pFCCs) during Chl breakdown, was characterized and partially purified. RCC reductase activity was present at all stages of barley leaf development and even in roots. The highest specific activity was found in senescent leaves, which were used to purify RCC reductase 1000-fold. Among the remaining three proteins, RCC reductase activity was most likely associated with a 55-kD protein. RCC reductase exhibited saturation kinetics for RCC, with an apparent Michaelis constant of 0.6 mM. The reaction depended on reduced ferredoxin and was sensitive to oxygen. Assays of purified RCC reductase with chemically synthesized RCC as a substrate yielded three different FCCs, two of which could be identified as the stereoisomeric pFCCs from canola (Brassica napus) (pFCC-1) and sweet pepper (Capsicum annuum) (pFCC-2), respectively. In the coupled reaction with Pheide a oxidase and RCC reductase, either pFCC-1 or pFCC-2 was produced, depending on the plant species employed as a source of RCC reductase. Data from 18 species suggest that the stereospecific action of RCC reductase is uniform within a plant family. << Less

  Plant Physiol. 115:677-682(1997) [PubMed] [EuropePMC]

• Molecular cloning, functional expression and characterization of RCC reductase, involved in chlorophyll catabolism.

  Wuethrich K.L., Bovet L., Hunziker P.E., Donnison I.S., Hoertensteiner S.

  Red chlorophyll catabolite (RCC) reductase (RCCR) and pheophorbide (Pheide) a oxygenase (PaO) catalyse the key reaction of chlorophyll catabolism, porphyrin macrocycle cleavage of Pheide a to a primary fluorescent catabolite (pFCC). RCCR was purified from barley and a partial gene sequence was clo ... >> More

  Red chlorophyll catabolite (RCC) reductase (RCCR) and pheophorbide (Pheide) a oxygenase (PaO) catalyse the key reaction of chlorophyll catabolism, porphyrin macrocycle cleavage of Pheide a to a primary fluorescent catabolite (pFCC). RCCR was purified from barley and a partial gene sequence was cloned (pHvRCCR). The gene was expressed at all stages of leaf development and in roots. By comparison with different databases, genomic sequences and expressed sequence tags similar to RCCR were found in phylogenetically diverse species, and activity of RCCR was demonstrated in two of them, Arabidopsis thaliana and Marchantia polymorpha. The gene of A. thaliana (AtRCCR) was employed for molecular cloning, heterologous expression and the production of polyclonal antibodies. With recombinant RCCR, the major product of RCC reduction was pFCC-1, but small quantities of its C1 epimer, pFCC-2, also accumulated. The reaction required reduced ferredoxin and was sensitive to oxygen. AtRCCR encoded a 35 kDa protein which was used for chloroplast import experiments. Upon transport, it was processed to a mature form of 31 kDa. The significance of cloning of RCCR is discussed in respect to the evolution of chlorophyll catabolism and to the cloning of PaO. << Less

  Plant J. 21:189-198(2000) [PubMed] [EuropePMC]

• Crystal structure of red chlorophyll catabolite reductase: enlargement of the ferredoxin-dependent bilin reductase family.

  Sugishima M., Kitamori Y., Noguchi M., Kohchi T., Fukuyama K.

  The key steps in the degradation pathway of chlorophylls are the ring-opening reaction catalyzed by pheophorbide a oxygenase and sequential reduction by red chlorophyll catabolite reductase (RCCR). During these steps, chlorophyll catabolites lose their color and phototoxicity. RCCR catalyzes the f ... >> More

  The key steps in the degradation pathway of chlorophylls are the ring-opening reaction catalyzed by pheophorbide a oxygenase and sequential reduction by red chlorophyll catabolite reductase (RCCR). During these steps, chlorophyll catabolites lose their color and phototoxicity. RCCR catalyzes the ferredoxin-dependent reduction of the C20/C1 double bond of red chlorophyll catabolite. RCCR appears to be evolutionarily related to the ferredoxin-dependent bilin reductase (FDBR) family, which synthesizes a variety of phytobilin pigments, on the basis of sequence similarity, ferredoxin dependency, and the common tetrapyrrole skeleton of their substrates. The evidence, however, is not robust; the identity between RCCR and FDBR HY2 from Arabidopsis thaliana is only 15%, and the oligomeric states of these enzymes are different. Here, we report the crystal structure of A. thaliana RCCR at 2.4 A resolution. RCCR forms a homodimer, in which each subunit folds in an alpha/beta/alpha sandwich. The tertiary structure of RCCR is similar to those of FDBRs, strongly supporting that these enzymes evolved from a common ancestor. The two subunits are related by noncrystallographic 2-fold symmetry in which the alpha-helices near the edge of the beta-sheet unique in RCCR participate in intersubunit interaction. The putative RCC-binding site, which was derived by superimposing RCCR onto biliverdin-bound forms of FDBRs, forms an open pocket surrounded by conserved residues among RCCRs. Glu154 and Asp291 of A. thaliana RCCR, which stand opposite each other in the pocket, likely are involved in substrate binding and/or catalysis. << Less

  J. Mol. Biol. 389:376-387(2009) [PubMed] [EuropePMC]

• In vivo participation of red chlorophyll catabolite reductase in chlorophyll breakdown.

  Pruzinska A., Anders I., Aubry S., Schenk N., Tapernoux-Luthi E., Muller T., Krautler B., Hortensteiner S.

  A central reaction of chlorophyll breakdown, porphyrin ring opening of pheophorbide a to the primary fluorescent chlorophyll catabolite (pFCC), requires pheophorbide a oxygenase (PAO) and red chlorophyll catabolite reductase (RCCR), with red chlorophyll catabolite (RCC) as a presumably PAO-bound i ... >> More

  A central reaction of chlorophyll breakdown, porphyrin ring opening of pheophorbide a to the primary fluorescent chlorophyll catabolite (pFCC), requires pheophorbide a oxygenase (PAO) and red chlorophyll catabolite reductase (RCCR), with red chlorophyll catabolite (RCC) as a presumably PAO-bound intermediate. In subsequent steps, pFCC is converted to different fluorescent chlorophyll catabolites (FCCs) and nonfluorescent chlorophyll catabolites (NCCs). Here, we show that RCCR-deficient Arabidopsis thaliana accumulates RCC and three RCC-like pigments during senescence, as well as FCCs and NCCs. We also show that the stereospecificity of Arabidopsis RCCR is defined by a small protein domain and can be reversed by a single Phe-to-Val exchange. Exploiting this feature, we prove the in vivo participation of RCCR in chlorophyll breakdown. After complementation of RCCR mutants with RCCRs exhibiting alternative specificities, patterns of chlorophyll catabolites followed the specificity of complementing RCCRs. Light-dependent leaf cell death observed in different RCCR-deficient lines strictly correlated with the accumulation of RCCs and the release of singlet oxygen, and PAO induction preceded lesion formation. These findings suggest that RCCR absence causes leaf cell death as a result of the accumulation of photodynamic RCC. We conclude that RCCR (together with PAO) is required for the detoxification of chlorophyll catabolites and discuss the biochemical role(s) for this enzyme. << Less

  Plant Cell 19:369-387(2007) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.