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Query: UMLS:C1832526 (PCC)
 5,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Synechocystis PCC 6803 as in other cyanobacteria, involvement of protein PII in the co-regulation of inorganic carbon and nitrogen metabolism was established based on post-translational modifications of the protein resulting from changes in the carbon/nitrogen regimes. Uptake of bicarbonate and nitrate in response to changes of the carbon and/or nitrogen regimes is altered in a PII-null mutant, indicating that both processes are under control of PII. Modulation of electron flow by addition of methyl viologen with or without duroquinol, or in a NAD(P)H dehydrogenase-deficient mutant, affects the phosphorylation level of PII. The redox state of the cells would thus act as a trigger for PII phosphorylation.
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PMID:Protein PII regulates both inorganic carbon and nitrate uptake and is modified by a redox signal in synechocystis PCC 6803. 1060 24

Six mutants (B1 to B6) that grew poorly in air on BG11 agar plates buffered at pH 8.0 were rescued after mutations were introduced into ndhB of wild-type (WT) Synechocystis sp. strain PCC 6803. In these mutants and a mutant (M55) lacking ndhB, CO(2) uptake was much more strongly inhibited than HCO(3)(-) uptake, i.e., the activities of CO(2) and HCO(3)(-) uptake in B1 were 9 and 85% of those in the WT, respectively. Most of the mutants grew very slowly or did not grow at all at pH 6.5 or 7.0 in air, and their ability to grow under these conditions was correlated with CO(2) uptake capacity. Detailed studies of B1 and M55 indicated that the mutants grew as fast as the WT in liquid at pH 8.0 under air, although they grew poorly on agar plates. The contribution of CO(2) uptake appears to be larger on solid medium. Five mutants were constructed by inactivating each of the five ndhD genes in Synechocystis sp. strain PCC 6803. The mutant lacking ndhD3 grew much more slowly than the WT at pH 6.5 under 50 ppm CO(2), although other ndhD mutants grew like the WT under these conditions and showed low affinity for CO(2) uptake. These results indicated the presence of multiple NAD(P)H dehydrogenase type I complexes with specific roles.
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PMID:Mutation of ndh genes leads to inhibition of CO(2) uptake rather than HCO(3)(-) uptake in Synechocystis sp. strain PCC 6803. 1076 63

Relative to ferredoxin:NADP(+) reductase (FNR) from chloroplasts, the comparable enzyme in cyanobacteria contains an additional 9 kDa domain at its amino-terminus. The domain is homologous to the phycocyanin associated linker polypeptide CpcD of the light harvesting phycobilisome antennae. The phenotypic consequences of the genetic removal of this domain from the petH gene, which encodes FNR, have been studied in Synechocystis PCC 6803. The in frame deletion of 75 residues at the amino-terminus, rendered chloroplast length FNR enzyme with normal functionality in linear photosynthetic electron transfer. Salt shock correlated with increased abundance of petH mRNA in the wild-type and mutant alike. The truncation stopped salt stress-inducible increase of Photosystem I-dependent cyclic electron flow. Both photoacoustic determination of the storage of energy from Photosystem I specific far-red light, and the re-reduction kinetics of P700(+), suggest lack of function of the truncated FNR in the plastoquinone-cytochrome b(6)f complex reductase step of the PS I-dependent cyclic electron transfer chain. Independent gold-immunodecoration studies and analysis of FNR distribution through activity staining after native polyacrylamide gelelectrophoresis showed that association of FNR with the thylakoid membranes of Synechocystis PCC 6803 requires the presence of the extended amino-terminal domain of the enzyme. The truncated DeltapetH gene was also transformed into a NAD(P)H dehydrogenase (NDH1) deficient mutant of Synechocystis PCC 6803 (strain M55) (T. Ogawa, Proc. Natl. Acad. Sci. USA 88 (1991) 4275-4279). Phenotypic characterisation of the double mutant supported our conclusion that both the NAD(P)H dehydrogenase complex and FNR contribute independently to the quinone cytochrome b(6)f reductase step in PS I-dependent cyclic electron transfer. The distribution, binding properties and function of FNR in the model cyanobacterium Synechocystis PCC 6803 will be discussed.
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PMID:Salt shock-inducible photosystem I cyclic electron transfer in Synechocystis PCC6803 relies on binding of ferredoxin:NADP(+) reductase to the thylakoid membranes via its CpcD phycobilisome-linker homologous N-terminal domain. 1077 58

Antibodies raised against NdhH and NdhB detected these proteins in the thylakoid membrane of Synechocystis sp. strain PCC 6803, but not in a purified cytoplasmic membrane. We conclude that NAD(P)H dehydrogenase is largely, if not exclusively, confined to the thylakoid membrane.
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PMID:Localization of NAD(P)H dehydrogenase in the cyanobacterium Synechocystis sp. strain PCC 6803. 1146 1

Cyanobacteria possess a CO(2)-concentrating mechanism that involves active CO(2) uptake and HCO(3)(-) transport. For CO(2) uptake, we have identified two systems in the cyanobacterium Synechocystis sp. strain PCC 6803, one induced at low CO(2) and one constitutive. The low CO(2)-induced system showed higher maximal activity and higher affinity for CO(2) than the constitutive system. On the basis of speculation that separate NAD(P)H dehydrogenase complexes were essential for each of these systems, we reasoned that inactivation of one system would allow selection of mutants defective in the other. Thus, mutants unable to grow at pH 7.0 in air were recovered after transformation of a DeltandhD3 mutant with a transposon-bearing library. Four of them had tags within slr1302 (designated cupB), a homologue of sll1734 (cupA), which is cotranscribed with ndhF3 and ndhD3. The DeltacupB, DeltandhD4, and DeltandhF4 mutants showed CO(2)-uptake characteristics of the low CO(2)induced system observed in wild type. In contrast, mutants DeltacupA, DeltandhD3, and DeltandhF3 showed characteristics of the constitutive CO(2)-uptake system. Double mutants impaired in one component of each of the systems were unable to take up CO(2) and required high CO(2) for growth. Phylogenetic analysis indicated that the ndhD3/ndhD4-, ndhF3/ndhF4-, and cupA/cupB-type genes are present only in cyanobacteria. Most of the cyanobacterial strains studied possess the ndhD3/ndhD4-, ndhF3/ndhF4-, and cupA/cupB-type genes in pairs. Thus, the two types of NAD(P)H dehydrogenase complexes essential for low CO(2)-induced and constitutive CO(2)-uptake systems associated with the NdhD3/NdhF3/CupA-homologues and NdhD4/NdhF4/CupB-homologues, respectively, appear to be present in these cyanobacterial strains but not in other organisms.
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PMID:Distinct constitutive and low-CO2-induced CO2 uptake systems in cyanobacteria: genes involved and their phylogenetic relationship with homologous genes in other organisms. 1156 54

The composition and dynamics of membrane protein complexes were studied in the cyanobacterium Synechocystis sp. PCC 6803 by two-dimensional blue native/SDS-PAGE followed by matrix-assisted laser-desorption ionization time of flight mass spectrometry. Approximately 20 distinct membrane protein complexes could be resolved from photoautotrophically grown wild-type cells. Besides the protein complexes involved in linear photosynthetic electron flow and ATP synthesis (photosystem [PS] I, PSII, cytochrome b6f, and ATP synthase), four distinct complexes containing type I NAD(P)H dehydrogenase (NDH-1) subunits were identified, as well as several novel, still uncharacterized protein complexes. The dynamics of the protein complexes was studied by culturing the wild type and several mutant strains under various growth modes (photoautotrophic, mixotrophic, or photoheterotrophic) or in the presence of different concentrations of CO2, iron, or salt. The most distinct modulation observed in PSs occurred in iron-depleted conditions, which induced an accumulation of CP43' protein associated with PSI trimers. The NDH-1 complexes, on the other hand, responded readily to changes in the CO2 concentration and the growth mode of the cells and represented an extremely dynamic group of membrane protein complexes. Our results give the first direct evidence, to our knowledge, that the NdhF3, NdhD3, and CupA proteins assemble together to form a small low CO2-induced protein complex and further demonstrate the presence of a fourth subunit, Sll1735, in this complex. The two bigger NDH-1 complexes contained a different set of NDH-1 polypeptides and are likely to function in respiratory and cyclic electron transfer. Pulse labeling experiments demonstrated the requirement of PSII activity for de novo synthesis of the NDH-1 complexes.
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PMID:Towards functional proteomics of membrane protein complexes in Synechocystis sp. PCC 6803. 1473 74

The subunit compositions of two types of NAD(P)H dehydrogenase complexes of Synechocystis sp. PCC 6803, NDH-1L and NDH-1M, were studied by two-dimensional blue-native/SDS-PAGE followed by electrospray tandem mass spectrometry. Fifteen proteins were observed in NDH-1L including hydrophilic subunits (NdhH, -K, -I, -J, -M, and -N) and hydrophobic subunits (NdhA, -B, -E, -G, -D1, and -F1). In addition, NdhL and a novel subunit, Ssl1690 (designated NdhO), were shown to be components of this complex. All subunits mentioned above were present in the NDH-1M complex except NdhD1 and NdhF1. NdhL and Ssl1690 (NdhO) were homologous to hypothetical proteins encoded by genomic DNA in higher plants, suggesting that chloroplast NDH-1 complexes contain related subunits. Diagnostic sequence motifs were found for both NdhL and NdhO homologous proteins. Analysis of ndhL deletion mutant (M9) revealed the presence of assembled NDH-1L and NDH-1M complexes, but these complexes appear to be functionally impaired in the absence of NdhL. Both NDH-1 complexes were absent in the ndhB deletion mutant (M55).
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PMID:Identification of NdhL and Ssl1690 (NdhO) in NDH-1L and NDH-1M complexes of Synechocystis sp. PCC 6803. 1554 34

To investigate the (co)expression, interaction, and membrane location of multifunctional NAD(P)H dehydrogenase type 1 (NDH-1) complexes and their involvement in carbon acquisition, cyclic photosystem I, and respiration, we grew the wild type and specific ndh gene knockout mutants of Synechocystis sp PCC 6803 under different CO2 and pH conditions, followed by a proteome analysis of their membrane protein complexes. Typical NDH-1 complexes were represented by NDH-1L (large) and NDH-1M (medium size), located in the thylakoid membrane. The NDH-1L complex, missing from the DeltaNdhD1/D2 mutant, was a prerequisite for photoheterotrophic growth and thus apparently involved in cellular respiration. The amount of NDH-1M and the rate of P700+ rereduction in darkness in the DeltaNdhD1/D2 mutant grown at low CO2 were similar to those in the wild type, whereas in the M55 mutant (DeltaNdhB), lacking both NDH-1L and NDH-1M, the rate of P700+ rereduction was very slow. The NDH-1S (small) complex, localized to the thylakoid membrane and composed of only NdhD3, NdhF3, CupA, and Sll1735, was strongly induced at low CO2 in the wild type as well as in DeltaNdhD1/D2 and M55. In contrast with the wild type and DeltaNdhD1/D2, which show normal CO2 uptake, M55 is unable to take up CO2 even when the NDH-1S complex is present. Conversely, the DeltaNdhD3/D4 mutant, also unable to take up CO2, lacked NDH-1S but exhibited wild-type levels of NDH-1M at low CO2. These results demonstrate that both NDH-1S and NDH-1M are essential for CO2 uptake and that NDH-1M is a functional complex. We also show that the Na+/HCO3- transporter (SbtA complex) is located in the plasma membrane and is strongly induced in the wild type and mutants at low CO2.
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PMID:Expression and functional roles of the two distinct NDH-1 complexes and the carbon acquisition complex NdhD3/NdhF3/CupA/Sll1735 in Synechocystis sp PCC 6803. 1554 42

The cyanobacterial plasma membrane is an essential cell barrier with functions such as the control of taxis, nutrient uptake and secretion. These functions are carried out by integral membrane proteins, which are difficult to identify using standard proteomic methods. In this study, integral proteins were enriched from purified plasma membranes of Synechocystis sp. PCC 6803 using urea wash followed by protein resolution in 1D SDS/PAGE. In total, 51 proteins were identified by peptide mass fingerprinting using MALDI-TOF MS. More than half of the proteins were predicted to be integral with 1-12 transmembrane helices. The majority of the proteins had not been identified previously, and include members of metalloproteases, chemotaxis proteins, secretion proteins, as well as type 2 NAD(P)H dehydrogenase and glycosyltransferase. The obtained results serve as a useful reference for further investigations of the address codes for targeting of integral membrane proteins in cyanobacteria.
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PMID:Proteomics of Synechocystis sp. PCC 6803. Identification of novel integral plasma membrane proteins. 1728 59

In cyanobacteria, respiratory electron transport takes place in close proximity to photosynthetic electron transport, because the complexes required for both processes are located within the thylakoid membranes. The balance of electron transport routes is crucial for cell physiology, yet the factors that control the predominance of particular pathways are poorly understood. Here we use a combination of tagging with green fluorescent protein and confocal fluorescence microscopy in live cells of the cyanobacterium Synechococcus elongatus PCC 7942 to investigate the distribution on submicron scales of two key respiratory electron donors, type-I NAD(P)H dehydrogenase (NDH-1) and succinate dehydrogenase (SDH). When cells are grown under low light, both complexes are concentrated in discrete patches in the thylakoid membranes, about 100-300 nm in diameter and containing tens to hundreds of complexes. Exposure to moderate light leads to redistribution of both NDH-1 and SDH such that they become evenly distributed within the thylakoid membranes. The effects of electron transport inhibitors indicate that redistribution of respiratory complexes is triggered by changes in the redox state of an electron carrier close to plastoquinone. Redistribution does not depend on de novo protein synthesis, and it is accompanied by a major increase in the probability that respiratory electrons are transferred to photosystem I rather than to a terminal oxidase. These results indicate that the distribution of complexes on the scale of 100-300 nm controls the partitioning of reducing power and that redistribution of electron transport complexes on these scales is a physiological mechanism to regulate the pathways of electron flow.
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PMID:Control of electron transport routes through redox-regulated redistribution of respiratory complexes. 2273 74


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