Psb30 contributes to structurally stabilise the Photosystem II complex in the thermophilic cyanobacterium Thermosynechococcus elongatus |
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Authors: | Miwa Sugiura Sayo Harada Hidenori Hayashi Yasuhiro Kashino |
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Affiliation: | a Cell-Free Science and Technology Research Center, and Venture Business Laboratory, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan b Department of Chemistry, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan c Department of Life Science, University of Hyogo, 3-2-1 Kohto, Kamigohri, Ako-gun, Hyogo 678-1297, Japan d iBiTec-S, CNRS URA 2096, CEA Saclay, 91191 Gif sur Yvette, France |
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Abstract: | A deletion mutant that lacks the Psb30 protein, one of the small subunits of Photosystem II, was constructed in a Thermosynechococcus elongatus strain in which the D1 protein is expressed from the psbA3 gene (WT*). The ΔPsb30 mutant appears more susceptible to photodamage, has a cytochrome b559 that is converted into the low potential form, and probably also lacks the PsbY subunit. In the presence of an inhibitor of protein synthesis, the ?Psb30 lost more rapidly the water oxidation function than the WT* under the high light conditions. These results suggest that Psb30 contributes to structurally and functionally stabilise the Photosystem II complex in preventing the conversion of cytochrome b559 into the low potential form. Structural reasons for such effects are discussed. |
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Keywords: | Car, β-carotene Chl, chlorophyll ChlD1, ChlD2, monomeric Chls that are bound to D1 and D2, respectively ChlzD1, ChlzD2, side-path redox-active Chls that are bound to D1 and D2, respectively CP43, Chl-binding 43 kDa protein CP47, Chl-binding 47 kDa protein Cyt, cytochrome DCBQ, 2,6-dichloro-p-benzoquinone EPR, electron paramagnetic resonance LP and HP form, low-potential and high-potential form MALDI-TOF, matrix-assisted laser desorption/ionisation time of flight MES, 2-(N-morpholino) ethanesulfonic acid MGDG, monogalactosyl-diacylglycerol MMOBS, observed molecular mass MMCALC, calculated molecular mass OEC, oxygen-evolving complex Pheo, pheophytin P680, primary electron donor PD1, P680 Chl on D1 PD2, P680 Chl on D2 PSII, Photosystem II QA, primary quinone acceptor QB, secondary quinone acceptor Sp, spectinomycin SQDG, sulfoquinovosyl-diacylglycerol Sm, streptomycin WT*, Thermosynechococcus elongatus strain with a His-tag on the C terminus at CP43 and in which the psbA1 and psbA2 genes are deleted 43-H, T. elongatus strain with a His-tag on the C terminus of CP43 |
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