Plant photosystem I (PSI) is one of the most intricate membrane complexes in nature. It comprises two complexes, a reaction center and light-harvesting complex (LHC), which together form the PSI–LHC supercomplex. The crystal structure of plant PSI was solved with two distinct crystal forms. The first, crystallized at pH 6.5, exhibited P21 symmetry; the second, crystallized at pH 8.5, exhibited P212121 symmetry. The surfaces involved in binding plastocyanin and ferredoxin are identical in both forms. The crystal structure at 2.6 Å resolution revealed 16 subunits, 45 transmembrane helices, and 232 prosthetic groups, including 143 chlorophyll a, 13 chlorophyll b, 27 β-carotene, 7 lutein, 2 xanthophyll, 1 zeaxanthin, 20 monogalactosyl diglyceride, 7 phosphatidyl diglyceride, 5 digalactosyl diglyceride, 2 calcium ions, 2 phylloquinone, and 3 iron sulfur clusters. The model reveals detailed interactions, providing mechanisms for excitation energy transfer and its modulation in one of nature's most efficient photochemical machine.
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April 2018
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A 3D rendering of a Ubiquitin protein molecule. In this issue of Biochemical Society Transactions, Ovaa and Vertegaal discuss the role of ubiquitination and SUMO proteins in conjugation and deconjugation machineries; for details, see pages 423–436.
Review Article|
February 27 2018
Structure of the plant photosystem I
Ido Caspy;
Ido Caspy
1Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Nathan Nelson
1Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
Correspondence: Nathan Nelson (nelson@tauex.tau.ac.il)
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Publisher: Portland Press Ltd
Received:
November 22 2017
Revision Received:
January 16 2018
Accepted:
January 22 2018
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society
2018
Biochem Soc Trans (2018) 46 (2): 285–294.
Article history
Received:
November 22 2017
Revision Received:
January 16 2018
Accepted:
January 22 2018
Citation
Ido Caspy, Nathan Nelson; Structure of the plant photosystem I. Biochem Soc Trans 17 April 2018; 46 (2): 285–294. doi: https://doi.org/10.1042/BST20170299
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