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-Structure paper
タイトル | Structural and functional analyses of photosystem II in the marine diatom . |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 116, Issue 35, Page 17316-17322, Year 2019 |
掲載日 | 2019年8月27日 |
著者 | Orly Levitan / Muyuan Chen / Xuyuan Kuang / Kuan Yu Cheong / Jennifer Jiang / Melissa Banal / Nikhita Nambiar / Maxim Y Gorbunov / Steven J Ludtke / Paul G Falkowski / Wei Dai / |
PubMed 要旨 | A descendant of the red algal lineage, diatoms are unicellular eukaryotic algae characterized by thylakoid membranes that lack the spatial differentiation of stroma and grana stacks found in green ...A descendant of the red algal lineage, diatoms are unicellular eukaryotic algae characterized by thylakoid membranes that lack the spatial differentiation of stroma and grana stacks found in green algae and higher plants. While the photophysiology of diatoms has been studied extensively, very little is known about the spatial organization of the multimeric photosynthetic protein complexes within their thylakoid membranes. Here, using cryo-electron tomography, proteomics, and biophysical analyses, we elucidate the macromolecular composition, architecture, and spatial distribution of photosystem II complexes in diatom thylakoid membranes. Structural analyses reveal 2 distinct photosystem II populations: loose clusters of complexes associated with antenna proteins and compact 2D crystalline arrays of dimeric cores. Biophysical measurements reveal only 1 photosystem II functional absorption cross section, suggesting that only the former population is photosynthetically active. The tomographic data indicate that the arrays of photosystem II cores are physically separated from those associated with antenna proteins. We hypothesize that the islands of photosystem cores are repair stations, where photodamaged proteins can be replaced. Our results strongly imply convergent evolution between the red and the green photosynthetic lineages toward spatial segregation of dynamic, functional microdomains of photosystem II supercomplexes. |
リンク | Proc Natl Acad Sci U S A / PubMed:31409711 / PubMed Central |
手法 | EM (サブトモグラム平均) |
解像度 | 10.4 - 26.0 Å |
構造データ | EMDB-0539: EMDB-0540: |
由来 |
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