The 28 kDa apoprotein of CP 26 in PS II binds copper

Arvidsson, Per-Ola; Bratt, Charlotte; Andréasson, Lars-Erik; Åkerlund, Hans‐Erik

doi:10.1007/bf00032825

Cited by 13 publications

(7 citation statements)

References 40 publications

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“…Some proteins of the oxygen evolving complex in Photosystem II were present, namely the 33 and 18 kDa (Ljungberg et al 1986) as well as the 37 kDa ferredoxin-NADP + oxidoreductase. The 37 kDa protein has previously been identified by N-terminal sequencing by Arvidsson et al (1993).…”

Section: Resultsmentioning

confidence: 99%

Purification and identification of the violaxanthin deepoxidase as a 43 kDa protein

et al. 1996

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Violaxanthin deepoxidase (VDE) has been purified from spinach (Spinacia oleracea) leaves. The purification included differential sonication of thylakoid membranes, differential (NH4)2SO4 fractionation, gel filtration chromatography and finally either hydrophobic interaction chromatography or anion exchange chromatography. A total purification of more than 5000-fold compared to the original thylakoids enabled the identification of a 43 kDa protein as the VDE, in contrast to earlier reported molecular weight of 54-60 kDa. A detailed comparison was made for the VDE activity and polypeptide pattern for the different fractions throughout the purification and the best correlation was always found for the 43 kDa protein. The highest specific activity obtained was 256 μmol g(-1) s(-1) protein, which is at least 10-fold higher than reported earlier. We estimate that there is 1 VDE molecule per 20-100 electron transport chains. The 43 kDa protein was N-terminally sequenced, after protection of cysteine residues with β-mercaptoethanol and iodoacetamid, and a unique sequence of 20 amino acids was obtained. The amino acid composition of the protein revealed a high abundance of charged and polar amino acids and remarkably, 11 cysteine residues. Two other proteins (39.5 kDa and 40 kDa) copurifying with VDE were also N-terminally sequenced. The N-terminal part of the 39.5 kDa protein showed complete sequence identity both with the N-terminal part of cyt b 6 and an internal sequence of polyphenol oxidase.

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Section: Resultsmentioning

confidence: 99%

Purification and identification of the violaxanthin deepoxidase as a 43 kDa protein

et al. 1996

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“…ciated with CP26 (Arvidsson et al 1993). It is an inter-The ZE has not yet been isolated, but Marin et al esting thought that ZE can be associated with chloro-(1996) found a gene involved in ABA biosynthesis, cor-phyll complexes in the photosynthetic apparatus.…”

Section: Addition Of Iodoacetamid (Iac) Prevents the Reversal Ofmentioning

confidence: 99%

The xanthophyll cycle, its regulation and components

Eskling¹,

Arvidsson²,

Åkerlund³

1997

Physiol Plant

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1997. The xanthophyll cycle, its regulation and components. -Physiol. Plant. 100: 806-816.During the last few years much interest has been focused on the photoprotective role of zeaxanthin. In excessive light zeaxanthin is rapidly formed in the xanthophyll cycle from violaxanthin, via the intermediate antheraxanthin, a reaction reversed in the dark. The role of zeaxanthin and the xanthophyll cycle in photoprotection, is based on fluorescence quenching measurements, and in many studies a good correlation to the amount of zeaxanthin (and antheraxanthin) has been found. Other suggested roles for the xanthophylls involve, protection against oxidative stress of lipids, participation in the blue light response, modulation of the membrane fluidity and regulation of abscisic acid synthesis. The enzyme violaxanthin de-epoxidase has recently been purified from spinach and lettuce as a 43-kDa protein. It was found as 1 molecule per 20-100 electron-transport chains. The gene has been cloned and sequenced from Lactuca sativa, Nicotiana tabacum and Arabidopsis thaliana. The transit peptide was characteristic of nuclear-encoded and lumen-localized proteins. The activity of violaxanthin de-epoxidase is controlled by the lumen pH. Thus, below pH 6.6 the enzyme binds to the thylakoid membrane. In addition ascorbate becomes protonated to ascorbic acid (pKa = 4.2) the true substrate (K^ = 0.1 mM) for the violaxanthin de-epoxidase. We present arguments for an ascorbate transporter in the thylakoid membrane. The enzyme zeaxanthin epoxidase requires FAD as a cofactor and appears to use ferredoxin rather than NADPH as a reductant. The zeaxanthin epoxidase has not been isolated but the gene has been sequenced and a functional protein of 72.5 kDa has been expressed. The xanthophyll cycle pigments are almost evenly distributed in the thylakoid membrane and at least part of the pigments appears to be free in the lipid matrix where we conclude that the conversion by violaxanthin de-epoxidase occurs.

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“…Surprisingly, Droppa and Horvath (1990) reported amounts of 5.7, 2.2, 2.5, 1.8 and 1.2 atoms Cu per 300 Chi molecules in spinach. Arvidsson et al (1993) isolated BBY from spinach with a Cu content that ranged between 0.1 and 1.0 atoms per 300 Chi molecules. Some of tbe authors attributed these substantial variations to loss of Cu during the preparative procedures.…”

Section: Presence Of Cu In Psii Preparationsmentioning

confidence: 99%

“…Both authors had earlier detected a reduction of a 29 kDa polypeptide in severely Cu-deficient chloroplasts, suggesting that this was a minor antenna complex of PSII. Arvidsson et al (1993) claimed that Cu was a constituent of the minor antenna complex CP26, and proposed that this could be the missing oxidase of the xanthophyll cycle. Early experiments with Cu-chelators had suggested a functional role for Cu in PSII-mediated electron transport (see references in Droppa and Horvath, 1990).…”

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Copper and photosystem II: A controversial relationship

Barón¹,

Arellano²,

Gorgé³

1995

Physiol Plant

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Gorge. J. 1995. Copper and photosystem 11: A controversial relationship. -Pbysiol. Plant. 94: 174-180. Copper is an essential micronutrient for higher plants and algae and has a direct impact on photosynthesis. It is a constituent of the primary electron donor in photosystem 1. the Cu-protein plastocyanin. Many authors have also described Cu as a constituent of photosystem 11 (PSII). However, high Cu concentrations inhibit the photosynthetic electron transport, especially in PSII. In addition, both Cu deficiency and Cu toxicity interfere with pigment and lipid biosynthesis and, consequently, with chloroplast ultrastructure thus negatively influencing the photosynthetic efficiency. In this review, the different functions proposed for the metal in PSII are reviewed. Wilh reference to the effect of toxic Cu on PSII, the polemic results concerning its mechanism of action and Cu-hinding sites are discussed. Other effects of Cu loxicity and Cu deprivation on the thylakoid membrane are also briefly described.

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The 28 kDa apoprotein of CP 26 in PS II binds copper

Cited by 13 publications

References 40 publications

Purification and identification of the violaxanthin deepoxidase as a 43 kDa protein

Purification and identification of the violaxanthin deepoxidase as a 43 kDa protein

The xanthophyll cycle, its regulation and components

Copper and photosystem II: A controversial relationship

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