Anti-oxidative Stress System in Cyanobacteria

Hosoya-Matsuda, Naomi; Motohashi, Ken; Yoshimura, Hidehisa; Nozaki, Atsuo; Inoue, Kazuhito; Ohmori, Masayuki; Hisabori, Toru

doi:10.1074/jbc.m411493200

Cited by 99 publications

(26 citation statements)

References 51 publications

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“…We therefore applied an in vitro NADPH-NTR system as an alternative source of reducing equivalent. Chloroplast Trxs, Trx-f and Trx-m, are efficiently reduced by the electrons from NADPH via NTR as well as the cytosolic Trx (36). By using this NADPH-NTR system, we observed a remarkable difference in the activation of CHLI1 when comparing Trx-f and Trx-m, because this system eliminated the possible increase in basal level of ATPase activity (Fig.…”

Section: Trx Controls the Atpase Activity And Redox State Of Chli1-mentioning

confidence: 83%

“…It has been shown that cyanobacterial magnesium chelatase is sensitive to thiol-modifying reagents, and cysteine residues in CHLI and CHLH are involved in this inactivation (30), suggesting that Trx-dependent regulation also exists in cyanobacteria. In Synechocystis, multiple genes for Trx and Trx-like proteins have been found (36); however, their roles in the redox regulation of metabolic enzymes are not fully understood. Screening of Trx target proteins in Synechocystis allowed the identification of numerous proteins that differed from those identified in chloroplasts (44).…”

Section: Discussionmentioning

confidence: 99%

“…The recombinant CHLI1 (1 M) in suspension buffer (50 l) was incubated for 1 h at 25°C with 50 M CuCl 2 or various concentrations of dithiothreitol (DTT) in the presence or absence of recombinant spinach Trx-f (35) or Trx-m (34). For in vitro reduction of CHLI1 by Trx, NADPH, and NADPH-dependent thioredoxin reductase (NTR), NTR from Arabidopsis was prepared (36). To assess the redox state of CHLI1, 4-acetoamide-4Ј-maleimidyl-stilbene-2,2Ј-disulfonate (AMS) (Invitrogen), a maleimidyl reagent that specifically modifies cysteine residues, was used.…”

Section: Expression and Purification Of Recombinant Chli1 Protein-mentioning

confidence: 99%

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The CHLI1 Subunit of Arabidopsis thaliana Magnesium Chelatase Is a Target Protein of the Chloroplast Thioredoxin

Ikegami

Yoshimura

Motohashi

et al. 2007

Journal of Biological Chemistry

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135

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Insertion of magnesium into protoporphyrin IX by magnesium chelatase is a key step in the chlorophyll biosynthetic pathway, which takes place in plant chloroplasts. ATP hydrolysis by the CHLI subunit of magnesium chelatase is an essential component of this reaction, and the activity of this enzyme is a primary determinant of the rate of magnesium insertion into the chlorophyll molecule (tetrapyrrole ring). Higher plant CHLI contains highly conserved cysteine residues and was recently identified as a candidate protein in a proteomic screen of thioredoxin target proteins (Balmer, Y., Koller, A., del Val, G., Manieri, W., Schurmann, P., and Buchanan, B. B. (2003) Proc. Natl. Acad. Sci. U. S. A. 100, 370 -375). To study the thioredoxin-dependent regulation of magnesium chelatase, we first investigated the effect of thioredoxin on the ATPase activity of CHLI1, a major isoform of CHLI in Arabidopsis thaliana. The ATPase activity of recombinant CHLI1 was found to be fully inactivated by oxidation and easily recovered by thioredoxin-assisted reduction, suggesting that CHLI1 is a target protein of thioredoxin. Moreover, we identified one crucial disulfide bond located in the C-terminal helical domain of CHLI1 protein, which may regulate the binding of the nucleotide to the N-terminal catalytic domain. The redox state of CHLI was also found to alter in a light-dependent manner in vivo. Moreover, we successfully observed stimulation of the magnesium chelatase activity in isolated chloroplasts by reduction. Our findings strongly suggest that chlorophyll biosynthesis is subject to chloroplast biogenesis regulation networks to coordinate them with the photosynthetic pathways in chloroplasts.The reactions encompassing higher plant chlorophyll biosynthesis consist of 12 enzymes that work in unison to produce chlorophyll a from 5-aminolevulinic acid and constitute one of the most important pathways for chloroplast biogenesis. Among the chlorophyll biosynthetic enzymes, magnesium chelatase (EC 6.6.1.1) catalyzes the insertion of Mg 2ϩ into protoporphyrin IX, the first dedicated step in chlorophyll biosynthesis. In (bacterio)chlorophyll a-producing prokaryotes (1), chlorophyll a-synthesizing bacteria, and higher plants, the magnesium chelatase complex consists of ϳ40-, ϳ70-, and ϳ140-kDa subunits named I, D, and H respectively (2, 3). The stoichiometry of these subunits within the magnesium chelatase complex as well as its complete three-dimensional structure is yet to be determined. From the biochemical analysis using recombinant subunits of magnesium chelatase from the photosynthetic bacteria Rhodobacter and cyanobacterium Synechocystis sp. PCC6803, it was determined that the largest H subunit binds protoporphyrin IX noncovalently (4), suggesting that the H subunit catalyzes the metal chelation reaction. Although ATP and Mg 2ϩ are required for the interaction between I and D subunits (5, 6), I-D complex formation is independent from the ATP hydrolysis activity of I subunit. In contrast, the ATP hydrolysis process is required for...

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Section: Trx Controls the Atpase Activity And Redox State Of Chli1-mentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Expression and Purification Of Recombinant Chli1 Protein-mentioning

confidence: 99%

See 1 more Smart Citation

The CHLI1 Subunit of Arabidopsis thaliana Magnesium Chelatase Is a Target Protein of the Chloroplast Thioredoxin

Ikegami

Yoshimura

Motohashi

et al. 2007

Journal of Biological Chemistry

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135

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“…The m-type of thioredoxin, encoded by slr0623 in Synechocystis (18,19), was also purified as described previously (20). These proteins were stored in a buffer that contained 20 mM HEPES-KOH (pH 7.5), 50 mM NaCl, and 20% (w/v) glycerol.…”

Section: Methodsmentioning

confidence: 99%

Regulation of Translation by the Redox State of Elongation Factor G in the Cyanobacterium Synechocystis sp. PCC 6803

Kojima

Motohashi

Morota

et al. 2009

Journal of Biological Chemistry

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Elongation factor G (EF-G), a key protein in translational elongation, was identified as a primary target of inactivation by reactive oxygen species within the translational machinery of the cyanobacterium Synechocystis sp. PCC 6803 (Kojima, K., Oshita, M., Nanjo, Y., Kasai, K., Tozawa, Y., Hayashi, H., and Nishiyama, Y. (2007) Mol. Microbiol. 65, 936 -947). In the present study, we found that inactivation of EF-G (Slr1463) by H 2 O 2 was attributable to the oxidation of two specific cysteine residues and formation of a disulfide bond. Substitution of these cysteine residues by serine residues protected EF-G from inactivation by H 2 O 2 and allowed the EF-G to mediate translation in a translation system in vitro that had been prepared from Synechocystis. The disulfide bond in oxidized EF-G was reduced by thioredoxin, and the resultant reduced form of EF-G regained the activity to mediate translation in vitro. Western blotting analysis showed that levels of the oxidized form of EF-G increased under strong light in a mutant that lacked NADPHthioredoxin reductase, indicating that EF-G is reduced by thioredoxin in vivo. These observations suggest that the translational machinery is regulated by the redox state of EF-G, which is oxidized by reactive oxygen species and reduced by thioredoxin, a transmitter of reducing signals generated by the photosynthetic transport of electrons. Reactive oxygen species (ROS)2 are produced as inevitable by-products of the light-driven reactions of photosynthesis. The superoxide radical, hydrogen peroxide (H 2 O 2 ), and the hydroxyl radical are produced as a result of the photosynthetic transport of electrons, whereas singlet state oxygen (singlet oxygen) is produced by the transfer of excitation energy (1). Exposure of the photosynthetic machinery to strong light promotes the production of ROS and gives rise to oxidative stress (1).Strong light rapidly inactivates photosystem II (PSII). This phenomenon is referred to as photoinhibition (2-4), and it occurs when the rate of photodamage to PSII exceeds the rate of the repair of photodamaged PSII (5). The actions of ROS in the photoinhibition of PSII have been studied extensively, and several mechanisms for photoinhibition have been proposed (5). Recent studies of the effects of ROS on photodamage and repair have revealed that ROS act primarily by inhibiting the repair of photodamaged PSII and not by damaging PSII directly (5-9). Such studies have also shown that photodamage to PSII is an exclusively light-dependent event; photodamage is initiated by disruption of the manganese cluster of the oxygen-evolving complex upon absorption of light, in particular UV and blue light, with subsequent damage to the reaction center upon absorption of visible light by chlorophylls (10 -12).

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“…Kobayashi et al (32) recently reported accumulation of the transcript for sll1621 when cells were cultured under light conditions in the presence of methylviologen, a strong reactive oxygen species inducer. hosoya-Matsuda et al (24) revealed that type ii Prx is the essential Prx indispensable for Synechocystis cells. in addition, they found that this type ii Prx has a remarkable glutathione peroxidase activity.…”

Section: Extracellular Proteases Of Antarctic and Mesophilic Strains mentioning

confidence: 99%

Differentially Secreted Proteins of Antarctic and Mesophilic Strains ofSynechocystis SalinaandChlorella Vulgarisafter UV-B and Temperature Stress Treatment

Rakleova

Pouneva

Dobrev

et al. 2013

Biotechnology & Biotechnological Equipment

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Anti-oxidative Stress System in Cyanobacteria

Cited by 99 publications

References 51 publications

The CHLI1 Subunit of Arabidopsis thaliana Magnesium Chelatase Is a Target Protein of the Chloroplast Thioredoxin

The CHLI1 Subunit of Arabidopsis thaliana Magnesium Chelatase Is a Target Protein of the Chloroplast Thioredoxin

Regulation of Translation by the Redox State of Elongation Factor G in the Cyanobacterium Synechocystis sp. PCC 6803

Differentially Secreted Proteins of Antarctic and Mesophilic Strains ofSynechocystis SalinaandChlorella Vulgarisafter UV-B and Temperature Stress Treatment

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