Biochemistry and Molecular Biology of the Xanthophyll Cycle

Yamamoto, Harry Y.; Bugos, Robert C.; Hieber, A. David

doi:10.1007/0-306-48209-6_16

Cited by 47 publications

(41 citation statements)

References 67 publications

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“…In higher plants, carotenoids are largely tetraterpenoid pigments of chloroplast and chromoplast membranes, characterized as a C 40 backbone with polyene chains. Carotenoids not only are important accessory pigments in the light-harvesting complex but also function as redox intermediates in the process of electron transfer in photosystem II (PS II) [1][2][3][4][5][6]. Moreover, carotenoids play important roles in photoprotection by quenching free radicals, singlet oxygen and other reactive oxygen species (ROS) derived from excessive light, thereby protecting plants from these oxidative insults [4,7].…”

Section: Introductionmentioning

confidence: 99%

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

et al. 2007

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Carotenoids, a class of natural pigments found in all photosynthetic organisms, are involved in a variety of physiological processes, including coloration, photoprotection, biosynthesis of abscisic acid (ABA) and chloroplast biogenesis. Although carotenoid biosynthesis has been well studied biochemically, the genetic basis of the pathway is not well understood. Here, we report the characterization of two allelic Arabidopsis mutants, spontaneous cell death1-1 (spc1-1) and spc1-2. The weak allele spc1-1 mutant showed characteristics of bleached leaves, accumulation of superoxide and mosaic cell death. The strong mutant allele spc1-2 caused a complete arrest of plant growth and development shortly after germination, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that SPC1 encodes a putative z-carotene desaturase (ZDS) in the carotenoid biosynthesis pathway. Analysis of carotenoids revealed that several major carotenoid compounds downstream of SPC1/ZDS were substantially reduced in spc1-1, suggesting that SPC1 is a functional ZDS. Consistent with the downregulated expression of CAO and PORB, the chlorophyll content was decreased in spc1-1 plants. In addition, expression of Lhcb1.1, Lhcb1.4 and RbcS was absent in spc1-2, suggesting the possible involvement of carotenoids in the plastid-to-nucleus retrograde signaling. The spc1-1 mutant also displays an ABA-deficient phenotype that can be partially rescued by the externally supplied phytohormone. These results suggest that SPC1/ZDS is essential for biosynthesis of carotenoids and plays a crucial role in plant growth and development.

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Section: Introductionmentioning

confidence: 99%

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

et al. 2007

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“…The low thylakoid lumen pH plays dual roles, one of which is to activate the violaxanthin deepoxidase (VDE) enzyme, which converts violaxanthin into antheraxanthin and then zeaxanthin as part of a xanthophyll cycle (Figure 1) (Yamamoto et al, 1999;Jahns et al, 2009). The other role of the low thylakoid lumen pH is to protonate one or more PSII proteins that are involved in qE (Horton and Ruban, 1992).…”

Section: Introductionmentioning

confidence: 99%

Lutein Accumulation in the Absence of Zeaxanthin Restores Nonphotochemical Quenching in the Arabidopsis thaliana npq1 Mutant

et al. 2009

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Plants protect themselves from excess absorbed light energy through thermal dissipation, which is measured as nonphotochemical quenching of chlorophyll fluorescence (NPQ). The major component of NPQ, qE, is induced by high transthylakoid DpH in excess light and depends on the xanthophyll cycle, in which violaxanthin and antheraxanthin are deepoxidized to form zeaxanthin. To investigate the xanthophyll dependence of qE, we identified suppressor of zeaxanthinless1 (szl1) as a suppressor of the Arabidopsis thaliana npq1 mutant, which lacks zeaxanthin. szl1 npq1 plants have a partially restored qE but lack zeaxanthin and have low levels of violaxanthin, antheraxanthin, and neoxanthin. However, they accumulate more lutein and a-carotene than the wild type. szl1 contains a point mutation in the lycopene b-cyclase (LCYB) gene. Based on the pigment analysis, LCYB appears to be the major lycopene b-cyclase and is not involved in neoxanthin synthesis. The Lhcb4 (CP29) and Lhcb5 (CP26) protein levels are reduced by 50% in szl1 npq1 relative to the wild type, whereas other Lhcb proteins are present at wild-type levels. Analysis of carotenoid radical cation formation and leaf absorbance changes strongly suggest that the higher amount of lutein substitutes for zeaxanthin in qE, implying a direct role in qE, as well as a mechanism that is weakly sensitive to carotenoid structural properties.

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“…Excess energy dissipation is catalyzed by the nonphotochemical quenching (NPQ) mechanism, whose full expression depends on the de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin (VAZ) by violaxanthin de-epoxidase, which is activated by low luminal pH (13). Although it is generally accepted that NPQ is developed in the Lhc antenna system, the identity of the actual protein subunit catalyzing the energy dissipation reaction is still a matter of debate.…”

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The Major Antenna Complex of Photosystem II Has a Xanthophyll Binding Site Not Involved in Light Harvesting

Caffarri¹,

Croce²,

Breton³

et al. 2001

Journal of Biological Chemistry

226

265

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We have characterized a xanthophyll binding site, called V1, in the major light harvesting complex of photosystem II, distinct from the three tightly binding sites previously described as L1, L2, and N1. Xanthophyll binding to the V1 site can be preserved upon solubilization of the chloroplast membranes with the mild detergent dodecyl-␣-D-maltoside, while an IEF purification step completely removes the ligand. Surprisingly, spectroscopic analysis showed that when bound in this site, xanthophylls are unable to transfer absorbed light energy to chlorophyll a. Pigments bound to sites L1, L2, and N1, in contrast, readily transfer energy to chlorophyll a. This result suggests that this binding site is not directly involved in light harvesting function. When violaxanthin, which in normal conditions is the main carotenoid in this site, is depleted by the de-epoxidation in strong light, the site binds other xanthophyll species, including newly synthesized zeaxanthin, which does not induce detectable changes in the properties of the complex. It is proposed that this xanthophyll binding site represents a reservoir of readily available violaxanthin for the operation of the xanthophyll cycle in excess light conditions.Light energy for higher plant photosynthesis is harvested by pigments including chlorophyll (Chl) 1 a, Chl b, and carotenoids bound to pigment binding proteins embedded into the thylakoid membrane. Each photosystem is made of two moieties: the core complex, containing Chl a and ␤-carotene bound to plastidencoded polypeptides, and the light harvesting system, made up of nuclear encoded proteins of the Lhc family which, besides Chl a, also bind Chl b and the three xanthophylls lutein, violaxanthin, and neoxanthin. LHCII is by far the major antenna complex, since it binds about 50% of total chlorophyll. It is composed of heterotrimeric complexes of the Lhcb1, -2, and -3 gene products (1). Electron crystallography and mutation analysis showed that each Lhcb1 subunit contains five Chl a and four Chl b binding sites, while three additional sites can bind either Chl a or Chl b. Chlorophyll ligands are amino acid side chains belonging to three trans-membrane ␣-helices or to neighbor Chl (2, 3) through coordination of the Mg 2ϩ atom at the center of each porphyrin. Within the pigment-protein complex are also located two carotenoid binding sites, called L1 and L2, cross-bracing helices A and B. These sites are occupied by lutein (L1) and by lutein (80%) and violaxanthin (20%) (L2) (4, 5). A third carotenoid binding site (N1), highly specific for neoxanthin, was localized in the C helix domain (6). Xanthophylls in sites L1, L2, and N1, are tightly bound to the complex even in very harsh conditions of purification. In addition, violaxanthin can be bound to LHCII when isolated by mild detergent treatment, while the interaction does not survive further purification steps, such as IEF, suggesting loose binding (7,8).Besides their role in light harvesting, xanthophylls are also involved in photoprotection by quenching 3 Chl...

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Biochemistry and Molecular Biology of the Xanthophyll Cycle

Cited by 47 publications

References 67 publications

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

Lutein Accumulation in the Absence of Zeaxanthin Restores Nonphotochemical Quenching in the Arabidopsis thaliana npq1 Mutant

The Major Antenna Complex of Photosystem II Has a Xanthophyll Binding Site Not Involved in Light Harvesting

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