Photosynthesis and phosphorylation of light‐harvesting chlorophyll <i>a/b</i>—protein in intact chloroplasts

Allen, John F.

doi:10.1016/0014-5793(84)80087-3

Cited by 14 publications

(5 citation statements)

References 16 publications

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“…Today, phosphoryiation of light-harvesting chlorophyll proteins is mainly discussed with respect to the regulation of the energy transfer to the reaction centers of photosystems I and 2 (Staehelin and Arnzten 1983, Allen 1984, Bennett 1984see also Miiier and Lyon 1985), In our study, simultaneous measurements of synthesis and phosphoryiation of LHC 2-apoproteins suggest that, at least in Chlamydomonas, phosphoryiation may also have a functional significance of the formation of the light-harvesting complex. We investigated this interdependence of synthesis and phosphoryiation of the LHC 2-apoproteins simply by eliminating cytoplasmic protein synthesis and looking at the time course of the residual phosphoryiation.…”

Section: Discussionsupporting

confidence: 51%

Protein synthesis and phosphorylation of light‐harvesting apoproteins in normal and chlorophyll b‐deficient Chlamydomonas reinhardii

Michel

Boschetti

1987

Physiologia Plantarum

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A, 1987, Protein synthesis and phosphoryiation of lightharvesting apoproteins in normal and chlorophyll 6-deficient Chlamydomonas reinhardii. -Physiol, Plantarum 69: 9-15, Phosphoryiation of polypeptides in whole cells and in chloroplasts of different strains of Chlamydomonas reinhardii was studied. Phosphoryiation In vivo was strongly reduced when cytopiasmic protein synthesis was inhibited either by anisomycin or by cycioheximide. In isolated chloroplasts these two inhibitors had no effect on labelling. The incorporation of ['-P]-phosphate into one of the apoproteins of the lightharvesting chlorophyll a/A-protein complex (LHC 2) was also studied in relation to its synthesis. In vivo, in a chlorophyll 6-deficient mutant and in its parent strain we found a pronounced relationship between synthesis and phosphoryiation of this LHC 2-apoprotein, Our results suggest that LHC 2-apoproteins, newly synthesized in the cytoplasm, are preferentially phosphorylated after synthesis. Together with the observation that phosphoryiation stili occurs in isolated chioroplasts we conclude that in vivo at least two levels of phosphoryiation of the LHC 2-apoproteins have to be clearly differentiated. One level involves the phosphoryiation of existing and the other of newly synthesized polypeptides. The biological significance of phosphoryiation of the LHC 2-apoproteins in vivo and probably also of other thyiakoid polypeptides is complex and not restricted to regulation of energy distribution between photosystems 1 and 2,Additional key words -Chloroplast.

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Section: Discussionsupporting

confidence: 51%

Protein synthesis and phosphorylation of light‐harvesting apoproteins in normal and chlorophyll b‐deficient Chlamydomonas reinhardii

Michel

Boschetti

1987

Physiologia Plantarum

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“…The decline of the fluorescence during phase 3 is an argument against a decreased rate of cytochrome f reduction. Changes in the energy distribution by phosphorylation of the light-harvesting chlorophyll a/b protein complex take place within several minutes [1,15,3] and therefore can not be responsible for the P-S decline as well as for phase 3 of the cytochrome f kinetics. The effect of cations on the distribution of energy between both photosystems does not play any role in view of the high cation concentrations in intact chloroplasts [14] and the 5mM MgC12 applied in our experiments with thylakoids.…”

Section: Discussionmentioning

confidence: 99%

Regulation of the photosynthetic electron transport during dark-light transitions by activation of the ferredoxin-NADP+-oxidoreductase in higher plants

Rühle¹,

Pschorn²,

Wild³

1987

Photosynth Res

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Absorbance changes associated with the oxidation and reduction of cytochrome f belong to the classical observations about the interaction of the two photosystems. A complex induction pattern of cytochrome f oxidation results, if both photosystems are excited simultaneously. This indicates a light-modulated regulation of the photosynthetic electron transport, which we examined for intact biological systems of decreasing complexity. The ferredoxin-NADP(+)-oxidoreductase (FNR) is suggested to be activated by light and inactivated in the dark. This is pointed out by the kinetics of variable fluorescence and by the influence of different artificial electron acceptors on the cytochrome f kinetics. The photoreduction of NADP(+) by carefully prepared thylakoids demonstrates the activation process directly.

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“…In the thylakoid membrane, the LHCP-IIs are assembled into the LHC-IIs with 1 to 2 kD of their NH2-termini oriented toward the stroma. Phosphorylation occurs on the exposed NH2-termini (Mullet 1983) by means of a membrane-bound protein kinase (Bennett 1979, Allen 1984Bennett et al 1987) whose activity is regulated by light via the redox state of the plastoquinone pool between the PS II and cytochrome br/f complexes. The protein kinase is activated when the pool of plastoquinone becomes reduced (Horton et al 1981).…”

Section: G Modification By Phosphorylationmentioning

confidence: 99%

Regulation and expression of the multigene family coding light-harvesting chlorophyll a/b-binding proteins of photosystem II

et al. 1988

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The current state of knowledge concerning the expression of the nuclear genes that code the light-harvesting chlorophyll a/b-binding polypeptides of photosystem II is presented. This review covers the structure of these genes, the complex multistep pathway involved in their expression, and the environmental and other factors which regulate their expression. Some of the effects of these factors are mediated, at least in part, at the level of transcription, but other effects can be explained only by the existence of multiple posttranscriptional regulatory steps.

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Photosynthesis and phosphorylation of light‐harvesting chlorophyll a/b—protein in intact chloroplasts

Cited by 14 publications

References 16 publications

Protein synthesis and phosphorylation of light‐harvesting apoproteins in normal and chlorophyll b‐deficient Chlamydomonas reinhardii

Protein synthesis and phosphorylation of light‐harvesting apoproteins in normal and chlorophyll b‐deficient Chlamydomonas reinhardii

Regulation of the photosynthetic electron transport during dark-light transitions by activation of the ferredoxin-NADP+-oxidoreductase in higher plants

Regulation and expression of the multigene family coding light-harvesting chlorophyll a/b-binding proteins of photosystem II

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