The PsbK Subunit is Required for the Stable Assembly and Stability of Other Small Subunits in the PSII complex in the Thermophilic Cyanobacterium Thermosynechococcus elongatus BP-1

Iwai, Masaru; Suzuki, Takehiro; Kamiyama, Akiko; Sakurai, Isamu; Dohmae, Naoshi; Inoue, Yasunori; Ikeuchi, Masahiko

doi:10.1093/pcp/pcq020

Cited by 31 publications

(18 citation statements)

References 27 publications

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“…2 and 3). Recently, it was shown that the removal of PsbK, which is close to PsbJ, in PsbA1-PSII resulted in the complete loss of Psb30 and partial loss of PsbZ (49). In the present work it is shown that the removal of PsbJ has no effect on the PsbK content, and maybe as a consequence, it has no effect on the content of Psb30 and PsbZ.…”

Section: Table 2 Assignment Observed and Calculated Molecular Massesupporting

confidence: 44%

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Sugiura

Iwai

Hayashi

et al. 2010

Journal of Biological Chemistry

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The main cofactors involved in the oxygen evolution activity of Photosystem II (PSII) are located in two proteins, D1 (PsbA) and D2 (PsbD). In Thermosynechococcus elongatus, a thermophilic cyanobacterium, the D1 protein is encoded by either the psbA 1 or the psbA 3 gene, the expression of which is dependent on environmental conditions. It has been shown that the energetic properties of the PsbA1-PSII and those of the PsbA3-PSII differ significantly (Sugiura, M., Kato, Y., Takahashi, R., Suzuki, H., Watanabe, T., Noguchi, T., Rappaport, F., and Boussac, A. (2010) Biochim. Biophys. Acta 1797, 1491-1499). In this work the structural stability of PSII upon a PsbA1/PsbA3 exchange was investigated. Two deletion mutants lacking another PSII subunit, PsbJ, were constructed in strains expressing either PsbA1 or PsbA3. The PsbJ subunit is a 4-kDa transmembrane polypeptide that is surrounded by D1 (i.e. PsbA1), PsbK, and cytochrome b 559 (Cyt b 559 ) in existing three-dimensional models. It is shown that the structural properties of the PsbA3/ ⌬PsbJ-PSII are not significantly affected. The polypeptide contents, the Cyt b 559 properties, and the proportion of PSII dimer were similar to those found for PsbA3-PSII. In contrast, in PsbA1/⌬PsbJ-PSII the stability of the dimer is greatly diminished, the EPR properties of the Cyt b 559 likely indicates a decrease in its redox potential, and many other PSII subunits are lacking. These results shows that the 21-amino acid substitutions between PsbA1 and PsbA3, which appear to be mainly conservative, must include side chains that are involved in a network of interactions between PsbA and the other PSII subunits. Photosystem II (PSII)2 catalyzes the light-driven water oxidation and plastoquinone reduction in cyanobacteria, algae, and plants. In cyanobacteria, its minimum structural unit capable of oxygen evolution consists of a membranous complex with 20 protein subunits, 17 of which are membrane-spanning proteins and 3 of which are extrinsic proteins. In the recent refined three-dimensional x-ray structures from 3.5 to 2.9 Å resolution using PSII core complex isolated from the thermophilic cyanobacterium Thermosynechococcus elongatus (1-3) the PSII complex is organized in dimers. A PSII monomer involves 35 chlorophyll molecules, 2 pheophytin molecules, 2 hemes, 1 non-heme iron, 4 manganese ions, 1 calcium ion, 2 (ϩ1) quinones, and at least 12 carotenoid molecules and 25 lipids. One or two chloride-binding sites were also localized (3-5). All cofactors in charge of the photosynthetic electron transport involving P 680 chlorophylls (P D1 (P 680 Chl on D1), P D2 (P 680 Chl on D2), and Chl D1 and Chl D2 (monomeric Chls bound to D1 and D2, respectively)), Pheo D1 , and the plastoquinones Q A and Q B are bound to amino acid residues of the D1 and D2 subunits. The redox active Tyr residues, Tyr Z and Tyr D , correspond to amino acids of D1-161 and D2-160, respectively. The catalytic center responsible for water oxidation, a Mn 4 Ca cluster, interacts with amino acid residues from D1 and CP...

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Section: Table 2 Assignment Observed and Calculated Molecular Massesupporting

confidence: 44%

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Sugiura

Iwai

Hayashi

et al. 2010

Journal of Biological Chemistry

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“…The oxygen-evolving PSII core complexes were purified from cells of the T. elongatus 47-H strain (63), in which a (His) 6 -tag was genetically attached to the carboxyl terminus of the CP47 subunit, using Ni 2+ -affinity column chromatography as described previously (64). The O 2 evolution activity of PSII core complexes was 2,500-2,800 μmol O 2 ·(mg Chl) −1 ·h −1 .…”

Section: Methodsmentioning

confidence: 99%

Redox potential of the terminal quinone electron acceptor Q_Bin photosystem II reveals the mechanism of electron transfer regulation

Kato

Nagao

Noguchi

2015

Proc. Natl. Acad. Sci. U.S.A.

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Photosystem II (PSII) extracts electrons from water at a Mn 4 CaO 5 cluster using light energy and then transfers them to two plastoquinones, the primary quinone electron acceptor Q A and the secondary quinone electron acceptor Q B . This forward electron transfer is an essential process in light energy conversion. Meanwhile, backward electron transfer is also significant in photoprotection of PSII proteins. Modulation of the redox potential (E m ) gap of Q A and Q B mainly regulates the forward and backward electron transfers in PSII. However, the full scheme of electron transfer regulation remains unresolved due to the unknown E m value of Q B . Here, for the first time (to our knowledge), the E m value of Q B reduction was measured directly using spectroelectrochemistry in combination with light-induced Fourier transform infrared difference spectroscopy. The E m (Q B − /Q B ) was determined to be approximately +90 mV and was virtually unaffected by depletion of the In oxygenic photosynthesis in plants and cyanobacteria, photosystem II (PSII) has an important function in light-driven water oxidation, a process that leads to the generation of electrons and protons for CO 2 reduction and ATP synthesis, respectively (1-3). Photosynthetic water oxidation also produces molecular oxygen as a byproduct, which is the source of atmospheric oxygen and sustains virtually all life on Earth. PSII reactions are initiated by light-induced charge separation between a chlorophyll (Chl) dimer (P680) and a pheophytin (Pheo) electron acceptor, leading to the formation of a P680 + Pheo− radical pair (4, 5). An electron hole on P680+ is transferred to a Mn 4 CaO 5 cluster, the catalytic center of water oxidation, via the redox-active tyrosine, Y Z (D1-Tyr161). At the Mn 4 CaO 5 cluster, water oxidation proceeds through a cycle of five intermediates denoted S n states (n = 0-4) (6, 7). On the electron acceptor side, the electron is transferred from Pheo − to the primary quinone electron acceptor Q A and then to the secondary quinone electron acceptor Q B (8, 9). Q A and Q B have many similarities: they consist of plastoquinone (PQ), are located symmetrically around a nonheme iron center, and interact with D2 and D1 proteins, respectively, in a similar manner (Fig. 1) (10, 11). However, they play significantly different roles in PSII (8, 9). Q A is only singly reduced to transfer an electron to Q B , whereas Q B accepts one or two electrons. When Q B is doubly reduced, the resultant Q B 2− takes up two protons to form plastoquinol (PQH 2 ), which is then released into thylakoid membranes. Differences between Q A and Q B could be caused by differences in the molecular interactions of PQ with surrounding proteins in Q A and Q B pockets, although the detailed mechanism remains to be clarified (12, 13).Electron transfer reactions in PSII are highly regulated by the spatial localization of redox components and their redox potentials (E m values). Both forward and backward electron transfers are important; backward electron transfers cont...

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“…S3, left). A role for PsbZ and Psb30 in binding Psb27 seems equally unlikely, given that the absence of PsbK in T. elongatus also destabilizes binding of PsbZ and Ycf12/Psb30 to CP43 (Iwai et al, 2010).…”

Section: Location Of Psb27 Within Psiimentioning

confidence: 99%

The Psb27 Assembly Factor Binds to the CP43 Complex of Photosystem II in the Cyanobacterium Synechocystis sp. PCC 6803

et al. 2011

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We have investigated the location of the Psb27 protein and its role in photosystem (PS) II biogenesis in the cyanobacterium Synechocystis sp. PCC 6803. Native gel electrophoresis revealed that Psb27 was present mainly in monomeric PSII core complexes but also in smaller amounts in dimeric PSII core complexes, in large PSII supercomplexes, and in the unassembled protein fraction. We conclude from analysis of assembly mutants and isolated histidine-tagged PSII subcomplexes that Psb27 associates with the "unassembled" CP43 complex, as well as with larger complexes containing CP43, possibly in the vicinity of the large lumenal loop connecting transmembrane helices 5 and 6 of CP43. A functional role for Psb27 in the biogenesis of CP43 is supported by the decreased accumulation and enhanced fragmentation of unassembled CP43 after inactivation of the psb27 gene in a mutant lacking CP47. Unexpectedly, in strains unable to assemble PSII, a small amount of Psb27 comigrated with monomeric and trimeric PSI complexes upon native gel electrophoresis, and Psb27 could be copurified with histidine-tagged PSI isolated from the wild type. Yeast two-hybrid assays suggested an interaction of Psb27 with the PsaB protein of PSI. Pulldown experiments also supported an interaction between CP43 and PSI. Deletion of psb27 did not have drastic effects on PSII assembly and repair but did compromise short-term acclimation to high light. The tentative interaction of Psb27 and CP43 with PSI raises the possibility that PSI might play a previously unrecognized role in the biogenesis/repair of PSII.

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The PsbK Subunit is Required for the Stable Assembly and Stability of Other Small Subunits in the PSII complex in the Thermophilic Cyanobacterium Thermosynechococcus elongatus BP-1

Cited by 31 publications

References 27 publications

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Redox potential of the terminal quinone electron acceptor Q_Bin photosystem II reveals the mechanism of electron transfer regulation

The Psb27 Assembly Factor Binds to the CP43 Complex of Photosystem II in the Cyanobacterium Synechocystis sp. PCC 6803

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The PsbK Subunit is Required for the Stable Assembly and Stability of Other Small Subunits in the PSII complex in the Thermophilic Cyanobacterium Thermosynechococcus elongatus BP-1

Cited by 31 publications

References 27 publications

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Differences in the Interactions between the Subunits of Photosystem II Dependent on D1 Protein Variants in the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Redox potential of the terminal quinone electron acceptor QBin photosystem II reveals the mechanism of electron transfer regulation

The Psb27 Assembly Factor Binds to the CP43 Complex of Photosystem II in the Cyanobacterium Synechocystis sp. PCC 6803

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Redox potential of the terminal quinone electron acceptor Q_Bin photosystem II reveals the mechanism of electron transfer regulation