Characterization of the light-regulated operon encoding the phycoerythrin-associated linker proteins from the cyanobacterium Fremyella diplosiphon

Federspiel, Nancy A.; Grossman, A. R.

doi:10.1128/jb.172.7.4072-4081.1990

Cited by 85 publications

(81 citation statements)

References 64 publications

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“…The protein alignment shown in Fig. 2 clearly shows that the C terminus of the SYNW2000 gene product has a strong homology to the cpeD gene products from F. diplosiphon (11,12) and Gloeobacter violaceus whereas its N terminus is homologous to Synechococcus sp. strain WH8102 and WH8020 mpeC gene products, PEII ␥ linkers (49).…”

Section: Resultsmentioning

confidence: 99%

Two Novel Phycoerythrin-Associated Linker Proteins in the Marine CyanobacteriumSynechococcussp. Strain WH8102

et al. 2005

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The recent availability of the whole genome of Synechococcus sp. strain WH8102 allows us to have a global view of the complex structure of the phycobilisomes of this marine picocyanobacterium. Genomic analyses revealed several new characteristics of these phycobilisomes, consisting of an allophycocyanin core and rods made of one type of phycocyanin and two types of phycoerythrins (I and II). Although the allophycocyanin appears to be similar to that found commonly in freshwater cyanobacteria, the phycocyanin is simpler since it possesses only one complete set of ␣ and ␤ subunits and two rod-core linkers (CpcG1 and CpcG2). It is therefore probably made of a single hexameric disk per rod. In contrast, we have found two novel putative phycoerythrin-associated linker polypeptides that appear to be specific for marine Synechococcus spp. The first one (SYNW2000) is unusually long (548 residues) and apparently results from the fusion of a paralog of MpeC, a phycoerythrin II linker, and of CpeD, a phycoerythrin-I linker. The second one (SYNW1989) has a more classical size (300 residues) and is also an MpeC paralog. A biochemical analysis revealed that, like MpeC, these two novel linkers were both chromophorylated with phycourobilin. Our data suggest that they are both associated (partly or totally) with phycoerythrin II, and we propose to name SYNW2000 and SYNW1989 MpeD and MpeE, respectively. We further show that acclimation of phycobilisomes to high light leads to a dramatic reduction of MpeC, whereas the two novel linkers are not significantly affected. Models for the organization of the rods are proposed.

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Section: Resultsmentioning

confidence: 99%

Two Novel Phycoerythrin-Associated Linker Proteins in the Marine CyanobacteriumSynechococcussp. Strain WH8102

et al. 2005

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“…These results suggested that either the response to low sulfate overrides CCA or that CCA is shut down during growth in low sulfate. We differentiated between these possibilities by analyzing CCA-controlled changes in RNA abundance for the RL-activated pcyA gene and the GL-activated cpeBA operon (6,22) during growth in sulfate-replete and sulfate-limited conditions. CCA still functioned during growth under sulfate-limited conditions, although the extent of CCA-mediated activation for all of these genes was only half of that measured for cells grown in sulfatereplete media (Fig.…”

Section: F Diplosiphonmentioning

confidence: 99%

“…Another gene upregulated in RL is pcyA, which encodes the enzyme required for the synthesis of phycocyanobilin, the PC and APC chromophore (5). In GL, cpc2 is downregulated, while cpeBA, which encodes the only set of PE ␣/␤ apoproteins, is upregulated (22,39). The CCA regulation of the known GL-active genes occurs through two distinct pathways, the Rca and the Cgi systems (33), while the Rca system, which operates at the transcriptional level, alone controls the RL upregulation of cpc2 and pcyA (5,37).…”

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Sulfate-Driven Elemental Sparing Is Regulated at the Transcriptional and Posttranscriptional Levels in a Filamentous Cyanobacterium

et al. 2011

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Sulfur is an essential nutrient that can exist at growth-limiting concentrations in freshwater environments. The freshwater cyanobacterium Fremyella diplosiphon (also known as Tolypothrix sp. PCC 7601) is capable of remodeling the composition of its light-harvesting antennae, or phycobilisomes, in response to changes in the sulfur levels in its environment. Depletion of sulfur causes these cells to cease the accumulation of two forms of a major phycobilisome protein called phycocyanin and initiate the production of a third form of phycocyanin, which possesses a minimal number of sulfur-containing amino acids. Since phycobilisomes make up approximately 50% of the total protein in these cells, this elemental sparing response has the potential to significantly influence the fitness of this species under low-sulfur conditions. This response is specific for sulfate and occurs over the physiological range of sulfate concentrations likely to be encountered by this organism in its natural environment. F. diplosiphon has two separate sulfur deprivation responses, with low sulfate levels activating the phycobilisome remodeling response and low sulfur levels activating the chlorosis or bleaching response. The phycobilisome remodeling response results from changes in RNA abundance that are regulated at both the transcriptional and posttranscriptional levels. The potential of this response, and the more general bleaching response of cyanobacteria, to provide sulfur-containing amino acids during periods of sulfur deprivation is examined.

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“…These changes in PBS structure help the cells maximize the absorption of prevalent wavelengths of light in the environment and maintain high rates of photosynthesis. In most light environments, which contain a mixture of RL and GL, the PBS exists in a form that is intermediate between the two extremes described above.In the filamentous cyanobacterium Fremyella diplosiphon, the regulation of CCA occurs predominantly at the level of transcription of three operons, cpcB2A2 (cpcB2A2H2I2D2 encodes the inducible PC, plus its associated linker polypeptides), cpeBA (encoding PE), and cpeCDE (encoding the PE linker polypeptides) (17,20,34,38,40,41). The activation of cpcB2A2 and suppression of cpeBA and cpeCDE in RL and the suppression of cpcB2A2 and activation of cpeBA and cpeCDE in GL are photoreversible processes; the transcriptional activity of these genes can be repeatedly altered by changes in light quality, with the final states of the operons determined by the final wavelength to which the organism is exposed.…”

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confidence: 99%

New classes of mutants in complementary chromatic adaptation provide evidence for a novel four-step phosphorelay system

1997

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Complementary chromatic adaptation appears to be controlled by a complex regulatory system with similarity to four-step phosphorelays. Such pathways utilize two histidine and two aspartate residues for signal transduction. Previous studies of the signaling system controlling complementary chromatic adaptation have uncovered two elements of this pathway, a putative sensor, RcaE, and a response regulator, RcaC. In this work, we describe a second response regulator controlling complementary chromatic adaptation, RcaF, and identify putative DNA binding and histidine phosphoacceptor domains within RcaC. RcaF is a small response regulator with similarity to Spo0F of Bacillus subtilis; the latter functions in the four-step phosphorelay system controlling sporulation. We have also determined that within this phosphorelay pathway, RcaE precedes RcaF, and RcaC is probably downstream of RcaE and RcaF. This signal transduction pathway is novel because it appears to use at least five, instead of four, phosphoacceptor domains in the phosphorelay circuit.Complementary chromatic adaptation (CCA) occurs in many cyanobacteria and is a consequence of the adjustment of the pigment-protein composition of the photosynthetic lightharvesting antenna system, called the phycobilisome (PBS) (5, 6). During CCA, the inner portion of the PBS (the core) is unaltered but the composition of the rods, which make up the outer regions of the PBS, can change dramatically (9, 10, 52). The optimal wavelengths of the visible spectrum that elicit the two extreme structural states of the rods are red light (RL) (maximum absorbance wavelength [A max ] Х 650 nm) and green light (GL) A max Х 540 nm) (18,24,54). In RL the rods are composed of the chromoprotein phycocyanin (PC) and its associated linker polypeptides. In GL, the rods contain primarily the chromoprotein phycoerythrin (PE) and its associated linker polypeptides. These changes in PBS structure help the cells maximize the absorption of prevalent wavelengths of light in the environment and maintain high rates of photosynthesis. In most light environments, which contain a mixture of RL and GL, the PBS exists in a form that is intermediate between the two extremes described above.In the filamentous cyanobacterium Fremyella diplosiphon, the regulation of CCA occurs predominantly at the level of transcription of three operons, cpcB2A2 (cpcB2A2H2I2D2 encodes the inducible PC, plus its associated linker polypeptides), cpeBA (encoding PE), and cpeCDE (encoding the PE linker polypeptides) (17,20,34,38,40,41). The activation of cpcB2A2 and suppression of cpeBA and cpeCDE in RL and the suppression of cpcB2A2 and activation of cpeBA and cpeCDE in GL are photoreversible processes; the transcriptional activity of these genes can be repeatedly altered by changes in light quality, with the final states of the operons determined by the final wavelength to which the organism is exposed.Isolation of two elements of the CCA signal transduction pathway, RcaE and RcaC, was achieved by complementation of black (FdBk) a...

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Characterization of the light-regulated operon encoding the phycoerythrin-associated linker proteins from the cyanobacterium Fremyella diplosiphon

Cited by 85 publications

References 64 publications

Two Novel Phycoerythrin-Associated Linker Proteins in the Marine CyanobacteriumSynechococcussp. Strain WH8102

Two Novel Phycoerythrin-Associated Linker Proteins in the Marine CyanobacteriumSynechococcussp. Strain WH8102

Sulfate-Driven Elemental Sparing Is Regulated at the Transcriptional and Posttranscriptional Levels in a Filamentous Cyanobacterium

New classes of mutants in complementary chromatic adaptation provide evidence for a novel four-step phosphorelay system

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