pH‐dependent photoautotrophic growth of specific photosystem II mutants lacking lumenal extrinsic polypeptides in <i>Synechocystis</i> PCC 6803

Eaton‐Rye, Julian J.; Shand, Jackie A.; Nicoll, William

doi:10.1016/s0014-5793(03)00432-0

Cited by 30 publications

(42 citation statements)

References 36 publications

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“…There is no doubt that the PsbA protein provides ligands for coordination of the Mn cluster and that the PsbO protein, which is not absolutely essential for water oxidation in cyanobacteria, helps to stabilize the Mn cluster and also Ca 2+ at the lumenal side of PS II. In addition, it has been shown that in plants the polypeptides PsbP and PsbQ have auxiliary functions in concentrating Ca 2+ and Cl À , while in cyanobacteria the polypeptides PsbU and PsbV, like PsbO, are located on the lumenal side of PS II (Shen et al 1992; Kamiya and Shen 2002;Eaton-Rye et al 2003). However, it is still not clear whether any of the intrinsic subunits of low molecular weight that are present in PS II, in addition to the major polypeptides, are involved in stabilizing the inorganic cofactors required for water oxidation (Debus 1992;Ke 2001).…”

Section: Introductionmentioning

confidence: 99%

On the functional significance of the polypeptide PsbY for photosynthetic water oxidation in the cyanobacterium Synechocystis sp. strain PCC 6803

et al. 2004

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Recent investigations have revealed that the cyanobacterial photosystem II complex contains more than 26 polypeptides. The functions of most of the low-molecular-mass polypeptides, including PsbY, have remained elusive. Here we present a comparative characterization of the wild-type Synechocystis sp. strain PCC 6803 and a PsbY-free mutant derived from it. The results show that growth of the PsbY-free mutant was comparable to that of the wild-type when cells were cultivated in complete BG11 medium or under initial manganese or chloride limitation, and when illuminated at 20 or 200 microE m(-2) s(-1). However, while growth rates of both the wild-type and the PsbY-free mutant were reduced when cells were cultivated in BG11 medium in the absence of calcium, the reduction was significantly greater in the case of the PsbY-free mutant. This differential effect on growth of the mutant relative to the wild-type in CaCl(2) deficient medium was detected when the cells were illuminated with high-intensity light (200 microE m(-2) s(-1)) but not when light levels were lower (20 microE m(-2) s(-1)). The differential effect on growth was associated with lower O(2) evolving activity in the mutant compared to wild-type cells. The mutant was also found to be more sensitive to photoinhibition, and showed an altered pattern of fluorescence emission at 77 K. In addition, mass spectrometric analysis revealed that PsbY-free cells cultivated in CaCl(2) sufficient medium (in which no growth reduction was observed) had a significantly higher O(2) evolution from hydrogen peroxide and a lower O(2) evolution from water under flash light illumination than wild-type cells. These results imply that photosystem II is slightly impaired in the PsbY-free mutant, and that the mutant is less capable of coping with low levels of Ca(2+) than the wild-type.

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Section: Introductionmentioning

confidence: 99%

On the functional significance of the polypeptide PsbY for photosynthetic water oxidation in the cyanobacterium Synechocystis sp. strain PCC 6803

et al. 2004

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“…strain PCC 6803 by identification of a number of pH-sensitive photosystem II (PSII) mutants that are able to grow photoautotrophically at pH 10 but not at pH 7.5 (8,54). Each of these pH-sensitive strains contains two mutations in PSII, including the absence of either the PsbO or PsbV luminal protein.…”

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confidence: 99%

Global Transcriptional Response of the Alkali-Tolerant CyanobacteriumSynechocystissp. Strain PCC 6803 to a pH 10 Environment

Summerfield

Sherman

2008

Appl Environ Microbiol

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Many cyanobacterial strains are able to grow at a pH range from neutral to pH 10 or 11. Such alkaline conditions favor cyanobacterial growth (e.g., bloom formation), and cyanobacteria must have developed strategies to adjust to changes in CO 2 concentration and ion availability. Synechocystis sp. strain PCC 6803 exhibits similar photoautotrophic growth characteristics at pH 10 and pH 7.5, and we examined global gene expression following transfer from pH 7.5 to pH 10 to determine cellular adaptations at an elevated pH. The strategies used to develop homeostasis at alkaline pH had elements similar to those of many bacteria, as well as components unique to phototrophic microbes. Some of the response mechanisms previously identified in other bacteria included upregulation of Na ؉ /H ؉ antiporters, deaminases, and ATP synthase. In addition, upregulated genes encoded transporters with the potential to contribute to osmotic, pH, and ion homeostasis (e.g., a water channel protein, a large-conductance mechanosensitive channel, a putative anion efflux transporter, a hexose/proton symporter, and ABC transporters of unidentified substrates). Transcriptional changes specific to photosynthetic microbes involved NADH dehydrogenases and CO 2 fixation. The pH transition altered the CO 2 /HCO 3 ؊ ratio within the cell, and the upregulation of three inducible bicarbonate transporters (BCT1, SbtA, and NDH-1S) likely reflected a response to this perturbed ratio. Consistent with this was increased transcript abundance of genes encoding carboxysome structural proteins and carbonic anhydrase. Interestingly, the transition to pH 10 resulted in increased abundance of transcripts of photosystem II genes encoding extrinsic and low-molecular-weight polypeptides, although there was little change in photosystem I gene transcripts.

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“…A mutant lacking proteins of the oxygen-evolving complex of PSII is able to grow at alkaline pH but not at neutral or acidic pH (Eaton-Rye et al, 2003). Furthermore, Synechocystis strains DNdhB, with a non-functional NAD(P)H dehydrogenase complex, and DNdhD3/NdhD4, with an inactivated CO 2 uptake system, grow at pH 8.3, but not at pH 7.5 (Zhang et al, 2004).…”

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SigC sigma factor is involved in acclimation to low inorganic carbon at high temperature in Synechocystis sp. PCC 6803

et al. 2010

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Inactivation of the sigC gene (sll0184), encoding the group 2 sigma factor SigC, leads to a heatsensitive phenotype of Synechocystis sp. PCC 6803. Cells of the DsigC strain grew poorly at 43 6C at pH 7.5 under ambient CO 2 conditions. Addition of inorganic carbon in the form of 3 % CO 2 or use of an alkaline growth medium (pH 8.3) restored the growth of the DsigC strain at 43 6C. These treatments compensate for the low concentration of inorganic carbon at high temperature. However, addition of organic carbon as glucose, pyruvate, succinate or 2-oxoglutarate did not restore growth of the DsigC strain at 43 6C. In the control strain, the amount of the SigC factor diminished after prolonged incubation at 43 6C if the pH of the growth medium was 7.5 or 6.7. Under alkaline conditions, the amount of the SigC factor remained constant at 43 6C and cells of the control strain grew better than at pH 7.5 or pH 6.7. The pH dependence of high-temperature growth was associated with changes in photosynthetic activity, indicating that the SigC factor is involved in adjustment of photosynthesis according to the amount of available inorganic carbon. Our results indicate that acclimation to low inorganic carbon is a part of acclimation to prolonged high temperature and that the SigC factor has a central role in this acclimation. INTRODUCTIONCyanobacteria are a group of evolutionarily ancient eubacteria that perform oxygenic photosynthesis, like higher plants and algae. According to the endosymbiosis theory, cyanobacteria are progenitors of plant chloroplasts. The ability of cyanobacteria to survive under a range of different environmental stress conditions makes them valuable model organisms for studies of molecular mechanisms of acclimation. In particular, the unicellular cyanobacterium Synechocystis sp. PCC 6803 (hereafter referred to as Synechocystis) has been extensively used in gene expression studies under a variety of different stress conditions (Huang et al., 2002;Suzuki et al., 2005; Osanai et al., 2006;Singh et al., 2006;Slabas et al., 2006;Tuominen et al., 2008). These and other studies have demonstrated that acclimation to changing environmental conditions requires changes in gene expression over a wide range of different functions. The sigma (s) subunit of RNA polymerase holoenzyme is a key determinant of promoter recognition and transcription initiation in eubacteria, and replacement of a s factor in RNA polymerase holoenzyme with another one switches the transcription pattern (Wösten, 1998).The genome of Synechocystis contains nine genes encoding s factors (Kaneko et al., 1996). The primary s factor SigA is essential for cell viability (Imamura et al., 2003). The sigB, sigC, sigD and sigE genes encode group 2 s factors that closely resemble the SigA factor but are not essential for cell viability . Recent studies show that group 2 s factors are important for acclimation of cyanobacteria to suboptimal conditions (Muro-Pastor et al., 2001a;Imamura et al., 2003;Osanai et al., 2005 Osanai et al., , 2006Singh et al., 2...

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pH‐dependent photoautotrophic growth of specific photosystem II mutants lacking lumenal extrinsic polypeptides in Synechocystis PCC 6803

Cited by 30 publications

References 36 publications

On the functional significance of the polypeptide PsbY for photosynthetic water oxidation in the cyanobacterium Synechocystis sp. strain PCC 6803

On the functional significance of the polypeptide PsbY for photosynthetic water oxidation in the cyanobacterium Synechocystis sp. strain PCC 6803

Global Transcriptional Response of the Alkali-Tolerant CyanobacteriumSynechocystissp. Strain PCC 6803 to a pH 10 Environment

SigC sigma factor is involved in acclimation to low inorganic carbon at high temperature in Synechocystis sp. PCC 6803

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