Sensing of Inorganic Carbon Limitation in <i>Synechococcus</i> PCC7942 Is Correlated with the Size of the Internal Inorganic Carbon Pool and Involves Oxygen

Woodger, Fiona J.; Badger, Murray R.; Price, G. Dean

doi:10.1104/pp.105.069146

Cited by 78 publications

(90 citation statements)

References 63 publications

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“…The acclimation to LC increased the affinity toward bicarbonate approximately 4-fold in both cultures (wildtype K 1/2 = 35.5 6 6.4 mM, mutant MP2 K 1/2 = 46.2 6 19.6 mM). Previous studies revealed similar C i affinities for HC cells (approximately 150 mM) that increased up to 10-fold during the first few hours after the shift from HC to LC conditions in Synechococcus 7942 (Woodger et al, 2003(Woodger et al, , 2005.…”

Section: Physiological Characterizationmentioning

confidence: 94%

“…The metabolites of these pathways changed similarly in LC-shifted wild-type cells as well as PII mutant cells. Whether instead of 2OG another metabolite specifically induced by LC conditions, such as 2PG (Marcus et al, 1983;Eisenhut et al, 2008a;Kaplan et al, 2008;Nishimura et al, 2008), or another internal signal, such as the internal pool of C i , as suggested by Woodger et al (2005), serves as the signal to induce the LC-specific acclimation processes needs additional investigation. The differences in the metabolome between the wild type and the MP2 mutant can be expected to be, to a large extent, the result of changes in the transcription of genes for specific enzymes of the central C and N metabolism.…”

Section: Comparison Of the Metabolome Of The Wild Type And Pii Mutantmentioning

confidence: 99%

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Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

et al. 2011

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The amount of inorganic carbon is one of the main limiting environmental factors for photosynthetic organisms such as cyanobacteria. Using Synechococcus elongatus PCC 7942, we characterized metabolic and transcriptomic changes in cells that had been shifted from high to low CO 2 levels. Metabolic phenotyping indicated an activation of glycolysis, the oxidative pentose phosphate cycle, and glycolate metabolism at lowered CO 2 levels. The metabolic changes coincided with a general reprogramming of gene expression, which included not only increased transcription of inorganic carbon transporter genes but also genes for enzymes involved in glycolytic and photorespiratory metabolism. In contrast, the mRNA content for genes from nitrogen assimilatory pathways decreased. These observations indicated that cyanobacteria control the homeostasis of the carbon-nitrogen ratio. Therefore, results obtained from the wild type were compared with the MP2 mutant of Synechococcus 7942, which is defective for the carbon-nitrogen ratio-regulating PII protein. Metabolites and genes linked to nitrogen assimilation were differentially regulated, whereas the changes in metabolite concentrations and gene expression for processes related to central carbon metabolism were mostly similar in mutant and wild-type cells after shifts to low-CO 2 conditions. The PII signaling appears to down-regulate the nitrogen metabolism at lowered CO 2 , whereas the specific shortage of inorganic carbon is recognized by different mechanisms.

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Section: Physiological Characterizationmentioning

confidence: 94%

Section: Comparison Of the Metabolome Of The Wild Type And Pii Mutantmentioning

confidence: 99%

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

et al. 2011

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“…Mutants-Tagged or untagged versions of CcmM where expressed from various shuttle vectors (detailed below) and expressed in either WT Synechococcus PCC7942 cells or in the ⌬ccmM markerless deletion mutant (17).…”

Section: Expression Of N-and C-terminally Tagged His 6 Ccmmmentioning

confidence: 99%

“…It is therefore probable that both forms are translated from the same gene transcript and that each form has specific functions within the carboxysome shell. Here we present a novel gene complementation approach that utilizes the carboxysomeless Synechococcus PCC7942 mutant ⌬ccmM (16,17) and wild type (WT) cells to investigate the binding partners of CcmM within carboxysomes. Plasmid DNA constructs containing chimeric forms of ccmM, coding for His 6 tags at both the N and C termini of CcmM, were introduced into both WT and ⌬ccmM cell types.…”

mentioning

confidence: 99%

Analysis of Carboxysomes from Synechococcus PCC7942 Reveals Multiple Rubisco Complexes with Carboxysomal Proteins CcmM and CcaA

Long

Badger

Whitney

et al. 2007

Journal of Biological Chemistry

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173

224

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In cyanobacteria, the key enzyme for photosynthetic CO 2 fixation, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), is bound within proteinaceous polyhedral microcompartments called carboxysomes. Cyanobacteria with Form IB Rubisco produce ␤-carboxysomes whose putative shell proteins are encoded by the ccm-type genes. To date, very little is known of the protein-protein interactions that form the basis of ␤-carboxysome structure. In an effort to identify such interactions within the carboxysomes of the ␤-cyanobacterium Synechococcus sp. PCC7942, we have used polyhistidine-tagging approaches to identify at least three carboxysomal subcomplexes that contain active Rubisco. In addition to the expected L 8 S 8 Rubisco, which is the major component of carboxysomes, we have identified two Rubisco complexes containing the putative shell protein CcmM, one of which also contains the carboxysomal carbonic anhydrase, CcaA. The complex containing CcaA consists of Rubisco and the full-length 58-kDa form of CcmM (M58), whereas the other is made up of Rubisco and a short 35-kDa form of CcmM (M35), which is probably translated independently of M58 via an internal ribosomal entry site within the ccmM gene. We also show that the high CO 2 -requiring ccmM deletion mutant (⌬ccmM) can achieve nearly normal growth rates at ambient CO 2 after complementation with both wild type and chimeric (His 6 -tagged) forms of CcmM. Although a significant amount of independent L 8 S 8 Rubisco is confined to the center of the carboxysome, we speculate that the CcmMCcaA-Rubisco complex forms an important assembly coordination within the carboxysome shell. A speculative carboxysome structural model is presented.Prokaryotic organisms are distinct from their eukaryotic counterparts by the absence of specialized membrane-bound compartments. Although it is commonly considered that prokaryotic cells do not compartmentalize cellular processes, there is growing evidence that cyanobacteria and some ␤-proteobacteria have the means to do so when certain enzymes need to be sequestered or protected for maximal catalytic activity (1-3). Carboxysomes, for example, are polyhedral protein microcompartments found in cyanobacteria and chemoautotrophic bacteria, which contain the majority of a cell's ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (4). These microcompartments are essential to the operation of the CO 2 -concentrating mechanism in cyanobacteria. The CO 2 -concentrating mechanism utilizes a number of inorganic carbon (C i , the sum of CO 2 and HCO 3 Ϫ ) transport systems to elevate cellular HCO 3 Ϫ concentrations prior to CO 2 fixation (for reviews, see Refs. 5 and 6). Rubisco is a hexadecameric enzyme with a core of eight large subunits (L 8 ) made up of four L 2 dimers, each containing two catalytic sites. Attached to each end of the L 8 core are four small subunits (S 8 ) that are necessary for catalytic competence (7). Rubisco carries out the CO 2 fixation process in the initial step of the Calvin cycle, yet it is characterized by ...

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“…CcmM mutants do not contain carboxysomes and have the hcr phenotype [20,[58][59][60], indicating that the protein is important for carboxysome structure and/or biogenesis.…”

Section: Ccmmmentioning

confidence: 99%

Carboxysomal carbonic anhydrases: Structure and role in microbial CO2 fixation

Cannon

Heinhorst

Kerfeld

2010

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

116

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Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO 2 concentrations by employing a CO 2 -concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO 2 -fixing enzyme, RubisCO. The efficiency of CO 2 fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate, CO 2 . There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle.3

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Sensing of Inorganic Carbon Limitation in Synechococcus PCC7942 Is Correlated with the Size of the Internal Inorganic Carbon Pool and Involves Oxygen

Cited by 78 publications

References 63 publications

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

Analysis of Carboxysomes from Synechococcus PCC7942 Reveals Multiple Rubisco Complexes with Carboxysomal Proteins CcmM and CcaA

Carboxysomal carbonic anhydrases: Structure and role in microbial CO2 fixation

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