A proteolytic enzyme degrading phycocyanin in the cyanobacterium Anabaena cylindrica

Foulds, I

doi:10.1016/0378-1097(77)90168-9

Cited by 15 publications

(15 citation statements)

References 3 publications

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“…These reserves consist of the major light-harvesting pigments phycocyanin and phycoerythrin, constituting up to 50% of total cell protein (Glazer, 1987 ;Tandeau de Marsac & Houmard, 1993), and cyanophycin, a copolymer of arginine and aspartic acid that is unique to cyanobacteria (Simon, 1987). During periods of N # starvation in Anabaena spp., phycocyanin is degraded by a specific protease, phycocyaninase (Foulds & Carr, 1977 ;Wood & Haselkorn, 1980 ;Thiel, 1990), and phycocyanin gene expression is switched off, probably as a result of transcriptional regulation (Johnson et al, 1988 ;Wealand et al, 1989). The enzymes for cyanophycin synthesis and breakdown are more active in Anabaena heterocysts than in vegetative cells (Gupta & Carr, 1981), prompting the speculation that cyanophycin may serve as a dynamic reservoir of newly assimilated N that can be used for biosynthesis (Carr, 1988).…”

Section: Heterocyst Developmentmentioning

confidence: 99%

Tansley Review No. 107. Heterocyst and akinete differentiation in cyanobacteria

1999

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Section: Heterocyst Developmentmentioning

confidence: 99%

Tansley Review No. 107. Heterocyst and akinete differentiation in cyanobacteria

1999

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“…(34), Anabaena (11,33), Synechococcus strain PCC 7002 (28), and Synechocystis strain PCC 6803 (10). The resulting decrease in chlorophyll and phycobilisome (PBS) content leads to a dramatic change in cell color from the normal blue-green to yellow-green, which is known as bleaching or chlorosis.…”

mentioning

confidence: 99%

Nitrogen or Sulfur Starvation Differentially Affects Phycobilisome Degradation and Expression of the nblA Gene in Synechocystis Strain PCC 6803

et al. 2001

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Nitrogen (N) limitation in cyanobacteria is well documented: a reduced growth rate is observed, accompanied by a cessation of phycobiliprotein synthesis and an ordered degradation of phycobilisomes (PBS). This leads to a dramatic bleaching phenomenon known as chlorosis. In Synechococcus strain PCC 7942, bleaching due to PBS degradation is also observed under sulfur (S) or phosphorus (P) limitation, and all three are under the control of the nblA gene product, a 59-amino-acid polypeptide which is overexpressed under N, S, and P starvation (J. L. Collier, and A. R. Grossman, EMBO J. 13:1039-1047, 1994). Cyanobase sequence data for Synechocystis strain PCC 6803 indicate the presence of two tandem open reading frames (sll0452 and sll0453) homologous to nblA. We cloned the two genes, identified a unique 5 mRNA end suggestive of a single transcription start site, and studied nblA expression under conditions of N or S starvation by Northern hybridization: transcripts were detected only under N starvation (no signal is detected in replete medium or with S starvation), whether nblA1 or nblA2 was used as a probe. Mutations in nblA1 and nblA2 were constructed by insertion of a kanamycin cassette; both mutations were nonbleaching under N starvation. Synechocystis strain PCC 6803 does not bleach under S starvation, consistent with the absence of nblA induction in these conditions. These results were confirmed by analysis of the PBS components: sequential degradation of phycocyanin and associated linkers was observed only under conditions of N starvation. This indicates differences between Synechocystis strain PCC 6803 and Synechococcus strain PCC 7942 in their regulatory and signaling pathways leading to N-and S-starved phenotypes.

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“…Thus, the lack of new phycobiliprotein synthesis appears to result from regulation at the mRNA level. The degradation of preexisting phycobiliproteins is due to the action of proteases which appear during nitrogen starvation (13,40) and whose genes are also apparently regulated by nitrogen starvation.…”

Section: Discussionmentioning

confidence: 99%

“…carbon; during periods of nitrogen starvation, cyanobacteria degrade almost all their phycobiliproteins (2). The activity of a phycobiliprotein-specific protease increases substantially during the first few hours of nitrogen starvation (13,40). In nitrogen-fixing cyanobacteria, phycobiliprotein degradation can provide the amino acids needed to synthesize nitrogenase and other proteins for fixing nitrogen.…”

mentioning

confidence: 99%

Structure and regulation of genes encoding phycocyanin and allophycocyanin from Anabaena variabilis ATCC 29413

et al. 1988

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Gene clones encoding phycocyanin and allophycocyanin were isolated from an Anabaena variabilis ATCC 29413-Charon 30 library by using the phycocyanin (cpc) genes of Agmenellum quadruplicatum and the allophycocyanin (apc) genes of Cyanophora paradoxa as heterologous probes. The A. variabiis cpcA and cpcB genes occur together in the genome, as do the apcA and apcB genes; the two sets of genes are not closely linked, however. The cpc and apc genes appear to be present in only one copy per genome. DNA-RNA hybridization analysis showed that expression of the cpc and apc genes is greatly decreased during nitrogen starvation; within 1 h no cpc or apc mRNA could be detected. The source of nitrogen for growth did not influence expression of the genes; vegetative cells from nitrogen-fixing and ammonia-grown cultures had approximately the same levels of cpc and apc mRNAs. Heterocysts had less than 5% as much cpc mRNA as vegetative cells from nitrogen-fixing cultures. Northern hybridization (RNA blot) analysis showed that the cpc genes are transcribed to give an abundant 1.4-kilobase (kb) RNA as well as two less prominent 3.8-and 2.6-kb species. The apc genes gave rise to two transcripts, a 1.4-kb predominant RNA and a minor 1.75-kb form.

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A proteolytic enzyme degrading phycocyanin in the cyanobacterium Anabaena cylindrica

Cited by 15 publications

References 3 publications

Tansley Review No. 107. Heterocyst and akinete differentiation in cyanobacteria

Tansley Review No. 107. Heterocyst and akinete differentiation in cyanobacteria

Nitrogen or Sulfur Starvation Differentially Affects Phycobilisome Degradation and Expression of the nblA Gene in Synechocystis Strain PCC 6803

Structure and regulation of genes encoding phycocyanin and allophycocyanin from Anabaena variabilis ATCC 29413

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