Structure and Function of Photosystem I

Webber, Andrew N.; Bingham, Scott E.

doi:10.1007/0-306-48204-5_17

Cited by 5 publications

(5 citation statements)

References 131 publications

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“…However, we do not think that this is the situation here. The biosynthesis and maintenance of C.reinhardtii PSI is well characterized (reviewed by Webber and Bingham, 1998), and LHC deficiency has not been observed in strains carrying deletion mutations in the core polypeptides of PSI (Girard‐Bascou et al ., 1987; Takahashi et al ., 1991). Likewise, mutants affected in LHC abundance do not show a linked PSI defect (Plumley and Schmidt, 1995).…”

Section: Resultsmentioning

confidence: 99%

The Crd1 gene encodes a putative di-iron enzyme required for photosystem I accumulation in copper deficiency and hypoxia in Chlamydomonas reinhardtii

Moseley

Quinn

Eriksson

et al. 2000

EMBO J

167

155

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Chlamydomonas reinhardtii adapts to copper deficiency by degrading apoplastocyanin and inducing Cyc6 and Cpx1 encoding cytochrome c6 and coproporphyrinogen oxidase, respectively. To identify other components in this pathway, colonies resulting from insertional mutagenesis were screened for copper‐ conditional phenotypes. Twelve crd (copper response defect) strains were identified. In copper‐deficient conditions, the crd strains fail to accumulate photosystem I and light‐harvesting complex I, and they contain reduced amounts of light‐harvesting complex II. Cyc6, Cpx1 expression and plastocyanin accumulation remain copper responsive. The crd phenotype is rescued by a similar amount of copper as is required for repression of Cyc6 and Cpx1 and for maintenance of plastocyanin at its usual stoichiometry, suggesting that the affected gene is a target of the same signal transduction pathway. The crd strains represent alleles at a single locus, CRD1, which encodes a 47 kDa, hydrophilic protein with a consensus carboxylate‐bridged di‐iron binding site. Crd1 homologs are present in the genomes of photosynthetic organisms. In Chlamydomonas, Crd1 expression is activated in copper‐ or oxygen‐deficient cells, and Crd1 function is required for adaptation to these conditions.

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Section: Resultsmentioning

confidence: 99%

The Crd1 gene encodes a putative di-iron enzyme required for photosystem I accumulation in copper deficiency and hypoxia in Chlamydomonas reinhardtii

Moseley

Quinn

Eriksson

et al. 2000

EMBO J

167

155

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“…Photosystem I (PSI) is a thylakoid‐embedded pigment–protein complex that performs light‐induced charge separation and drives electron transfer from plastocyanin to ferredoxin. In C. reinhardtii , PSI is made of 13 subunits: PsaA, B, C and J are chloroplast‐encoded, whereas PsaD, E, F, G, H, K, L, N and O are nucleus‐encoded (for a review, see Webber and Bingham, 1998). The core components of PSI are two large transmembrane subunits, PsaA and PsaB, which share strong sequence similarity and may have arisen from gene duplication (reviewed in Baymann et al , 2001).…”

Section: Introductionmentioning

confidence: 99%

Biogenesis of PSI involves a cascade of translational autoregulation in the chloroplast of Chlamydomonas

Wostrikoff¹,

Girard‐Bascou²,

Wollman³

et al. 2004

EMBO J

107

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Photosystem I comprises 13 subunits in Chlamydomonas reinhardtii, four of which-the major reaction center I subunits PsaA and PsaB, PsaC and PsaJ-are chloroplast genome-encoded. We demonstrate that PSI biogenesis involves an assembly-governed regulation of synthesis of the major chloroplast-encoded subunits where the presence of PsaB is required to observe significant rates of PsaA synthesis and the presence of PsaA is required to observe significant rates of PsaC synthesis. Using chimeric genes expressed in the chloroplast, we show that these regulatory processes correspond to autoregulation of translation for PsaA and PsaC. The downregulation of translation occurs at some early stage since it arises from the interaction between unassembled PsaA and PsaC polypeptides and 5 0 untranslated regions of psaA and psaC mRNAs, respectively. These assembly-dependent autoregulations of translation represent two new instances of a control by epistasy of synthesis process that turns out to be a general feature of protein expression in the chloroplast of C. reinhardtii.

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“…The product of psaE, the PsaE subunit, is involved in the interaction of PSI with ferredoxin, whereas the psaB product, PsaB, is a component of the reaction center core (Obokata et al 1993, Scheller et al 1997, Webber and Bingham 1999.…”

Section: Photosynthesis Is Involved In the Light Induction Of Psi Genesmentioning

confidence: 99%

“…Photosystem I (PSI) is a light-driven plastocyaninferredoxin oxidoreductase in the thylakoid membrane of chloroplasts, and consists of subunits encoded by both the chloroplast and nuclear genomes (Obokata et al 1993, Scheller et al 1997, Webber and Bingham 1999. Genes for PSI subunits are activated in response to light stimuli in both etiolated seedlings and in green photosynthetically active cells (Rodermel and Bogorad 1985, Brunner et al 1991, Salvador et al 1993, Yamamoto et al 1995.…”

Section: Introductionmentioning

confidence: 99%

Dual Roles of Photosynthetic Electron Transport in Photosystem I Biogenesis: Light Induction of mRNAs and Chromatic Regulation at Post-mRNA Level

Matsuo¹,

Obokata²

2002

Plant and Cell Physiology

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;Light regulation of photosystem I (PSI) biogenesis was studied in a unicellular green alga, Chlamydomonas reinhardtii. When Chlamydomonas cells were transferred from darkness to the light, mRNAs for both nuclear-and chloroplast-encoded PSI subunits were induced in concert. This light induction was inhibited by photosynthetic electron transport (PET) inhibitors, 3-(3,4 dichlorophenyl)-1,1-dimethylurea and 2,5-dibromo-3-methyl-6 isopropyl-pbenzoquinone, but not by an uncoupler, carbonyl cyanide m-chlorophenylhydrazone. This indicated that PET plays a pivotal role in the light induction of PSI subunit mRNAs, but that photophosphorylation is not necessary. When we irradiated the Chlamydomonas cells with PSI-light (695 nm) or PSII-light (644 nm), which makes the plastoquinone pool oxidative and reductive, respectively, PSII-light caused the accumulation of PSI proteins more abundantly than did PSI-light. However, there was no difference for the PSI subunit mRNA levels between these light sources. From these results, we conclude that PET plays dual roles in the regulation of PSI biogenesis in Chlamydomonas: when cells are illuminated, PET first induces the PSI subunit mRNAs irrespective of the redox state of the intersystem electron carriers, and then their redox state fine-tunes PSI biogenesis at translational and/or post-translational steps to fulfil the chromatic adaptation.

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Structure and Function of Photosystem I

Cited by 5 publications

References 131 publications

The Crd1 gene encodes a putative di-iron enzyme required for photosystem I accumulation in copper deficiency and hypoxia in Chlamydomonas reinhardtii

The Crd1 gene encodes a putative di-iron enzyme required for photosystem I accumulation in copper deficiency and hypoxia in Chlamydomonas reinhardtii

Biogenesis of PSI involves a cascade of translational autoregulation in the chloroplast of Chlamydomonas

Dual Roles of Photosynthetic Electron Transport in Photosystem I Biogenesis: Light Induction of mRNAs and Chromatic Regulation at Post-mRNA Level

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