Site-directed mutagenesis of the psbC gene of photosystem II: isolation and functional characterization of CP43-less photosystem II core complexes

Rögner, Matthias; Chisholm, Dexter A.; Diner, Bruce A.

doi:10.1021/bi00236a009

Cited by 80 publications

(56 citation statements)

References 49 publications

(63 reference statements)

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“…The complex has been found in similar mutants (54,55) and a significantly elevated psbA transcript level had been noted (24). Our finding that the highest label in D1 is observed in the RC47 complex while only a minimal amount of the D1 protein was found in RC complexes as well as in the free fraction is remarkable.…”

Section: Discussionsupporting

confidence: 76%

Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex in Synechocystis PCC 6803

Komenda

Reisinger

Müller

et al. 2004

Journal of Biological Chemistry

163

164

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Accumulation of monomer and dimer photosystem (PS) II reaction center core complexes has been analyzed by two-dimensional Blue-native/SDS-PAGE in Synechocystis PCC 6803 wild type and in mutant strains lacking genes psbA, psbB, psbC, psbDIC/DII, or the psbEFLJ operon. In vivo pulse-chase radiolabeling experiments revealed that mutant cells assembled PSII precomplexes only. In ⌬psbC and ⌬psbB, assembly of reaction center cores lacking CP43 and reaction center complexes was detected, respectively. In ⌬psbA, protein subunits CP43, CP47, D2, and cytochrome b 559 were synthesized, but proteins did not assemble. Similarly, in ⌬psbD/C lacking D2, and CP43, the de novo synthesized proteins D1, CP47, and cytochrome b 559 did not form any mutual complexes, indicating that assembly of the reaction center complex is a prerequisite for assembly with core subunits CP47 and CP43. Finally, although CP43 and CP47 accumulated in ⌬psbEFLJ, D2 was neither expressed nor accumulated. We, furthermore, show that the amount of D2 is high in the strain lacking D1, whereas the amount of D1 is low in the strain lacking D2. We conclude that expression of the psbEFLJ operon is a prerequisite for D2 accumulation that is the key regulatory step for D1 accumulation and consecutive assembly of the PSII reaction center complex. The photosystem II (PSII)1 reaction center core (RCC) complex of higher plants, algae, and cyanobacteria can be subdivided into a heterodimer containing D1 and D2, the antenna proteins CP47 and CP43, and a large number of low molecular weight integral membrane proteins including the ␣ and ␤ subunits of cytochrome b 559 (␣ and ␤ cytochrome b 559 ) (1-3). The heterodimer and antenna proteins are essential for binding the prosthetic groups needed for energy and electron transfer (4) as well as for binding the multitude of plastid-encoded small subunits, e.g. Psb-H, -J, -K, -L, and Psb-T, which affect the function of PSII (5-8). Furthermore, plastid-encoded subunit psbZ has been shown to be required for attachment of CP26 during assembly of PSII-LHC supercomplexes, whereas the nucleusencoded subunit psbW was demonstrated to be required for RCC dimer formation (9 -11). The role of plastid-encoded subunits Psb-I, -M, and -N and the nucleus-encoded small subunits Psb-R, and X remains unclear. A striking feature of PSII is the fast turnover of the D1 protein that is believed to be required for PSII repair and restoration of its photochemical activity after photoinactivation (12, 13). Maintaining PSII function may require selective replacement of this central PSII subunit including an efficient apparatus to recognize inactive complexes, and remove damaged and insert a new D1 copy (5, 14, 15). Zhang et al. (16) suggested that D1 replacement in higher plants may occur cotranslationally in a PSII subcomplex consisting of at least D2 and CP47, hence eliminating the need for complete disassembly and de novo assembly from PSII subunits.Cyanobacteria are an excellent model organism to study PSII assembly. The strain used most frequently i...

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Section: Discussionsupporting

confidence: 76%

Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex in Synechocystis PCC 6803

Komenda

Reisinger

Müller

et al. 2004

Journal of Biological Chemistry

163

164

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“…First, D1 turnover was dramatically inhibited in a ⌬CP43⌬FtsH double mutant compared with the parental ⌬CP43 strain, and there was a substantial increase in the level of the PSII subcomplex RC47 (35). This result suggests that inactivating ftsH (slr0228) might be a useful way to obtain mutants that accumulate sufficient amounts of PSII complexes with modified structure and/or function for advanced biophysical and biochemical studies.…”

Section: Discussionmentioning

confidence: 99%

“…To confirm more conclusively that selective D1 turnover was indeed impaired in the absence of FtsH (slr0228), we decided to analyze the effect of disrupting ftsH (slr0228) in a mutant that shows a much higher level of selective D1 turnover than WT. Such a mutant is ⌬CP43, which lacks the psbC gene encoding the inner PSII antenna CP43 (35). Strain ⌬CP43 accumulates reduced amounts of PSII (10 -20% of WT level) in the form of RC47 and shows intense radiolabeling of D1 in pulse-labeling experiments, suggesting a high degree of selective D1 replacement (28).…”

Section: Ftsh (Slr0228) Is Required For Selective D1 Replacement In Wmentioning

confidence: 99%

The FtsH Protease slr0228 Is Important for Quality Control of Photosystem II in the Thylakoid Membrane of Synechocystis sp. PCC 6803

Komenda

Barker

Kuviková

et al. 2006

Journal of Biological Chemistry

139

149

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The cyanobacterium Synechocystis sp. PCC 6803 contains four members of the FtsH protease family. One of these, FtsH (slr0228), has been implicated recently in the repair of photodamaged photosystem II (PSII) complexes. We have demonstrated here, using a combination of blue native PAGE, radiolabeling, and immunoblotting, that FtsH (slr0228) is required for selective replacement of the D1 reaction center subunit in both wild type PSII complexes and in PSII subcomplexes lacking the PSII chlorophyll a-binding subunit CP43. To test whether FtsH (slr0228) has a more general role in protein quality control in vivo, we have studied the synthesis and degradation of PSII subunits in wild type and in defined insertion and missense mutants incapable of proper assembly of the PSII holoenzyme. We discovered that, when the gene encoding FtsH (slr0228) was disrupted in these strains, the overall level of assembly intermediates and unassembled PSII proteins markedly increased. Pulse-chase experiments showed that this was due to reduced rates of degradation in vivo. Importantly, analysis of epitope-tagged and green fluorescent protein-tagged strains revealed that slr0228 was present in the thylakoid and not the cytoplasmic membrane. Overall, our results show that FtsH (slr0228) plays an important role in controlling the removal of PSII subunits from the thylakoid membrane and is not restricted to selective D1 turnover.All cellular organisms possess quality control mechanisms to prevent the accumulation of unwanted proteins (1). Of current interest are the processes by which damaged and unassembled proteins are removed from the thylakoid membrane, which is the location of the protein complexes involved in oxygenic photosynthetic electron transport in cyanobacteria and chloroplasts (2). Side reactions associated with the light reactions of photosynthesis lead to the production of a variety of potentially hazardous molecules (e.g. reactive oxygen species) that can oxidize components, such as amino acid side chains and pigment cofactors (3). Ultimately, unless the damage is repaired, there is a net reduction in photosynthetic performance known as photoinhibition (for review see Ref. 4). As yet, the repair pathways and, more generally, the quality control processes involved in the assembly of the thylakoid membrane protein complexes and removal of aberrant proteins remain poorly understood.One component that is especially prone to photodamage is the photosystem II (PSII) 2 complex, which is composed of over 25 membrane and peripheral proteins and is responsible for the light-driven oxidation of water and reduction of plastoquinone (5). The D1 protein, together with the homologous D2 protein, binds the cofactors involved in electron transfer through the complex (6). The D1 subunit is also the chief target for light-induced damage in PSII and undergoes rapid synthesis and degradation in the light to maintain PSII activity in what is termed the PSII repair cycle (4).Although the precise mechanism of PSII repair is unknown, recent work ha...

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“…A stable CP47RC subcore complex assembles within the thylakoid membrane of cyanobacteria in the deletion mutant lacking the psbC gene for CP43 [82]. These complexes can be isolated and are active in electron transport but inactive in O 2 evolution, presumably due to an incomplete Mn cluster.…”

Section: Role Of Protein Subunits In Assemblymentioning

confidence: 99%

Photoassembly of the water-oxidizing complex in photosystem II

Dasgupta

Ananyev

Dismukes

2008

Coordination Chemistry Reviews

167

121

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The light-driven steps in the biogenesis and repair of the inorganic core comprising the O 2 -evolving center of oxygenic photosynthesis (photosystem II water-oxidation complex, PSII-WOC) are reviewed. These steps, known collectively as photoactivation, involve the photoassembly of the free inorganic cofactors to the cofactor-depleted PSII-(apo-WOC) driven by light and produce the active O 2 -evolving core comprised of Mn 4 CaO x Cl y . We focus on the functional role of the inorganic components as seen through the competition with non-native cofactors ("inorganic mutants") on water oxidation activity, the rate of the photoassembly reaction, and on structural insights gained from EPR spectroscopy of trapped intermediates formed in the initial steps of the assembly reaction. A chemical mechanism for the initial steps in photoactivation is given that is based on these data. Photoactivation experiments offer the powerful insights gained from replacement of the native cofactors, which together with the recent X-ray structural data for the resting holoenzyme provide a deeper understanding of the chemistry of water oxidation. We also review some new directions in research that photoactivation studies have inspired that look at the evolutionary history of this remarkable catalyst.

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Site-directed mutagenesis of the psbC gene of photosystem II: isolation and functional characterization of CP43-less photosystem II core complexes

Cited by 80 publications

References 49 publications

Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex in Synechocystis PCC 6803

Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex in Synechocystis PCC 6803

The FtsH Protease slr0228 Is Important for Quality Control of Photosystem II in the Thylakoid Membrane of Synechocystis sp. PCC 6803

Photoassembly of the water-oxidizing complex in photosystem II

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