Chlorophyll Metabolism

Ulrich Eckhardt, Humboldt Universität zu Berlin, Berlin, Germany
Bernhard Grimm, Humboldt Universität zu Berlin, Berlin, Germany

Published online: September 2007

DOI: 10.1002/9780470015902.a0020084

The two pathways for chlorophyll biosynthesis and catabolism of plants are located in distinct cellular compartments. While the entire biosynthesis of chlorophyll from the first committed metabolic precursor, 5-aminolaevulinic acid, occurs in plastids, chlorophyll breakdown starts in plastids and the final non-fluorescent breakdown products are deposited in vacuoles. The current understanding about both pathways in a diverse range of photosynthetic organisms including photosynthetic bacteria, algae and higher plants is outlined in the following report. It is quite obvious that the photosynthetic organisms evolved a complex control of these two pathways to enable specific adaptation to various environmental conditions.

Keywords: pigment biosynthesis; photosynthesis; light acclimation; photosensitization; senescence; primary metabolism

Figure 1. Structure of chlorophyll a and chlorophyll b (left side) and bacteriochlorophyll a and bacteriochlorophyll b (right side). The major esterifying alcohol (5 R) is phytol in chlorophyll a and b, geranylgeraniol in bacteriochlorophyll a, and phytadienol in bacteriochlorophyll b.
Figure 2. Flow chart of the metabolic pathway of tetrapyrrole biosynthesis towards the end products chlorophyll and protohaem. Potential feedback control mechanisms in the metabolic pathway of tetrapyrroles are indicated. The synthesis of 5-aminolaevulinate from glutamate is the rate-limiting step of tetrapyrrole biosynthesis. Feedback regulation on the enzymes of the 5-aminolaevulinic acid pathway can start out from various sites: at the level of haem formation, at the level of protochlorophyllide reduction and at the beginning of the Mg porphyrin branch.
Figure 3. Compartmentation of the biosynthetic pathway of tetrapyrroles and the catabolic pathway of chlorophyll.
Figure 4. The pathway of chlorophyll catabolism. Chlorophyllide a is the central molecule that connects the biosynthetic and the catabolic pathway as well as the ‘chlorophyll cycle’. ALA, 5-aminolaevulinic acid; CAO, chlorophyll(ide) a oxygenase; CAR, 7-hydroxychlorophyll(ide) a reductase; CBR, chlorophyll(ide) b reductase; Chl, chlorophyll; Chlase, chlorophyllase; Chlide, chlorophyllide; CS, chlorophyll synthase; PAO, phaeophorbide a oxygenase; pFCC, primary fluorescent chlorophyll catabolite; Phaeide a, phaeophorbide a; Pchlide, protochlorophyllide; RCC, red chlorophyll catabolite; RCCR, RCC reductase.
Figure 5. Structure and absorption spectra of three selected chlorophyll catabolites: (a) phaeophorbide a, (b) primary fluorescent chlorophyll catabolite and (c) non-fluorescent chlorophyll catabolite.
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 References
    book Alberti M, Burke DH and Hearst JH (1995) "Structure and sequence of the photosynthesis gene cluster". In: Blankenship RE, Madigan MT and Bauer CE (eds) Anoxygenic Photosynthetic Bacteria, pp. 1083–1106. The Hague: Kluwer Academic.
    Goslings D, Meskauskiene R, Kim C et al. (2004) Concurrent interactions of heme and FLU with Glu tRNA reductase (HEMA1), the target of metabolic feedback inhibition of tetrapyrrole biosynthesis, in dark- and light-grown Arabidopsis plants. Plant Journal 40: 957–967.
    book Grimm B, Porra R, Rüdiger W and Scheer H (eds). (2006) "Chlorophylls and Bacteriochlorophylls: Biochemistry, Biophysics, Functions and Applications". Advances in Photosynthesis and Respiration, vol. 25. Dordrecht, The Netherlands: Springer. ISBN 1-4020-4515-8.
    Hendry GAF, Houghton JD and Brown SB (1987) Chlorophyll degradation. A biological enigma. New Phytologist 107: 255–302.
    Hörtensteiner S (2006) Chlorophyll degradation during senescence. Annual Review of Plant Biology 57: 55–77.
    Kräutler B, Jaun B, Bortlik K-H, Schellenberg M and Matile P (1991) On the enigma of chlorophyll degradation: the constitution of a secoporphyrinoid catabolite. Angewandte Chemie. International Ed. In English 30: 1315–1318.
    Pruinska A, Tanner G, Aubry S et al. (2005) Chlorophyll breakdown in senescent Arabidopsis leaves. Characterization of chlorophyll catabolites and of chlorophyll catabolic enzymes involved in the degreening reaction. Plant Physiology 139: 52–63.
    Reinbothe S, Reinbothe C, Apel K and Lebedev N (1996) Evolution of chlorophyll biosynthesis – the challenge to survive photooxidation. Cell 86: 703–705.
    Surpin M, Larkin RM and Chory J (2002) Signal transduction between the chloroplast and the nucleus. Plant Cell 14(Suppl): S327–S338.
    Suzuki Y, Amano T and Shioi Y (2006) Characterization and cloning of the chlorophyll-degrading enzyme pheophorbidase from cotyledons of radish. Plant Physiology 140: 716–725.
    Watanabe N, Che FS, Iwano M et al. (2001) Dual targeting of spinach protoporphyrinogen oxidase II to mitochondria and chloroplasts by alternative use of two in-frame initiation codons. Journal of Biological Chemistry 276: 20474–20481.
    book Willstätter R and Stoll A (eds) (1913) "Die Wirkungen der Chlorophyllase". In: Untersuchungen über Chlorophyll. Methoden und Ergebnisse, pp. 172–187. Berlin: Springer [In German].
    Yao N, Eisfelder BJ, Marvin J and Greenberg JT (2004) The mitochondrion – an organelle commonly involved in programmed cell death in Arabidopsis thaliana. The Plant Journal 40: 596–610.
 Further Reading
    book Blankenship RE (2002) Molecular Mechanisms of Photosynthesis. Oxford: Blackwell Science.
    book Smith AG and Witty M (eds) (2001) Heme, Chlorophyll and Bilins – Methods and Protocols. New Jersey, USA: Humana Press.
    Tanaka A and Tanaka R (2006) Chlorophyll metabolism. Current Opinions in Plant Biology 9: 1–8.

Related Sub-Topics:

Cell Compartments and Cellular Organelles | Other Biomolecules: Structure, Function, Metabolism | Photosynthesis
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Article Title: Chlorophyll Metabolism
 
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Eckhardt, Ulrich, and Grimm, Bernhard(Sep 2007) Chlorophyll Metabolism. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0020084]