The primary structure of a cDNA for PsaN, encoding an extrinsic lumenal polypeptide of barley photosystem I

Knoetzel, Jürgen; Simpson, David J. W.

doi:10.1007/bf00014940

Cited by 39 publications

(14 citation statements)

References 35 publications

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“…It does not bind any cofactors and is not required for NADP + photoreduction. Recently a barley cDNA clone encoding the PsaN subunit of P S I was isolated (Knoetzel and Simpson 1993). The mature PsaN is 85 amino acids in length, with no putative membranespanning region.…”

Section: Psanmentioning

confidence: 99%

Function and organization of Photosystem I polypeptides

Chitnis

et al. 1995

Photosynth Res

119

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Photosystem I functions as a plastocyanin:ferredoxin oxidoreductase in the thylakoid membranes of chloroplasts and cyanobacteria. The PS I complex contains the photosynthetic pigments, the reaction center P700, and five electron transfer centers (A0, A1, FX, FA, and FB) that are bound to the PsaA, PsaB, and PsaC proteins. In addition, PS I complex contains at least eight other polypeptides that are accessory in their functions. Recent use of cyanobacterial molecular genetics has revealed functions of the accessory subunits of PS I. Site-directed mutagenesis is now being used to explore structure-function relations in PS I. The overall architecture of PSI complex has been revealed by X-ray crystallography, electron microscopy, and biochemical methods. The information obtained by different techniques can be used to propose a model for the organization of PS I. Spectroscopic and molecular genetic techniques have deciphered interaction of PS I proteins with the soluble electron transfer partners. This review focuses on the recent structural, biochemical and molecular genetic studies that decipher topology and functions of PS I proteins, and their interactions with soluble electron carriers.

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Section: Psanmentioning

confidence: 99%

Function and organization of Photosystem I polypeptides

Chitnis

et al. 1995

Photosynth Res

119

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“…Seven proteins possessing a bipartite presequence have been identified. These include the 16kDa (16K), 23 kDa (23K) and 33 kDa (33K) subunits of the photosystem II oxygen-evolving complex [ 14,26], plastocyanin [24], the CFo-II subunit of the ATP synthase [12] and the photosystem I subunits PSI-N [16] and PSI-F [25]. Plastocyanin is a soluble protein, the 16K, 23K, 33K and PSI-N components are hydrophilic extrinsic subunits of their respective complexes, while the PSI-F and CFo-II subunits are partly hydrophilic and partly hydrophobic members of their respective complexes.…”

mentioning

confidence: 99%

Import of the barley PSI-F subunit into the thylakoid lumen of isolated chloroplasts

Mp¹,

Vs²,

Knoetzel

et al. 1994

Plant Mol Biol

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A full-length cDNA clone encoding the PSI-F subunit of barley photosystem I has been isolated and sequenced. The open reading frame encodes a precursor polypeptide with a deduced molecular mass of 24837 Da. The barley PSI-F precursor contains a bipartite presequence with characteristics similar to the presequences of proteins destined to the thylakoid lumen. In vitro import studies demonstrate that an in vitro synthesized precursor is transported across the chloroplast envelope and directed to the thylakoid membrane, where it accumulates in a protease-resistant form. Incubation of the precursor with a chloroplast stromal extract results in processing to a form intermediate in size between the precursor and mature forms. Hydrophobicity analysis of the barley PSI-F protein reveals a hydrophobic region predicted to be a membrane spanning alpha-helix. The hydrophobic nature of PSI-F combined with a bipartite presequence is unusual. We postulate that the second domain in the bipartite presequence of the PSI-F precursor proteins is required to ensure the proper orientation of PSI-F in the thylakoid membrane. The expression of the PsaF gene is light-induced similar to other barley photosystem I genes.

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“…Since previous studies (6, 23) have localized MnSOD activity to the P. boryanum membrane fraction, these additional Nterminal residues may encode a signal sequence. The 41-residue, putative signal sequence of SodA1 exhibits similarity to the beginning of a PSI reaction center subunit, PSI-N, from barley (Hordeum vulgare L.) (16). The N terminus of PSI-N represents both a transit sequence which directs the subunit into the chloroplast and a signal sequence which directs the protein through the thylakoid membrane, where it can become associated with PSI.…”

Section: Vol 177 1995 Cyanobacterial Superoxide Dismutase Genes 965mentioning

confidence: 99%

Characterization of four superoxide dismutase genes from a filamentous cyanobacterium

Campbell

Laudenbach

1995

J Bacteriol

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By using an oligonucleotide probe constructed from a conserved region of amino acids located in the carboxyl-terminal end of superoxide dismutase (SOD) proteins, four SOD genes were cloned from the cyanobacterium Plectonema boryanum UTEX 485. One of these genes, designated sodB, encoded an FeSOD enzyme, while the remaining three genes, designated sodA1, sodA2, and sodA3, encoded MnSOD enzymes. To investigate the expression of these four genes, total cellular RNA was isolated from P. boryanum UTEX 485 cells grown under various conditions and RNA gel blot analysis was carried out. Results indicated that sodB and sodA1 were constitutively expressed, although sodB expression was partially repressed in cells grown under conditions of iron stress. sodA2 transcripts, which were not detectable in control cells, accumulated to high levels in cells treated with methyl viologen or in cells grown under conditions of iron or nitrogen stress. However, under microaerobic conditions, iron and nitrogen stress failed to induce sodA2, indicating that multiple factors affect the regulation of sodA2. While discrete transcripts were not detected for sodA3, hybridization was observed under a number of conditions, including those which increased the accumulation of sodA2 transcripts. Additionally, there were high levels of the sodA3 transcript detected in a P. boryanum UTEX 485 mutant strain resistant to methyl viologen treatment.

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The primary structure of a cDNA for PsaN, encoding an extrinsic lumenal polypeptide of barley photosystem I

Cited by 39 publications

References 35 publications

Function and organization of Photosystem I polypeptides

Function and organization of Photosystem I polypeptides

Import of the barley PSI-F subunit into the thylakoid lumen of isolated chloroplasts

Characterization of four superoxide dismutase genes from a filamentous cyanobacterium

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