Structure of the plant photosystem I

2018 ◽  
Vol 46 (2) ◽  
pp. 285-294 ◽  
Author(s):  
Ido Caspy ◽  
Nathan Nelson
Keyword(s):  
Crystal Structure ◽  
Photosystem I ◽  
Excitation Energy Transfer ◽  
Transmembrane Helices ◽  
Iron Sulfur Clusters ◽  
Crystal Forms ◽  
Light Harvesting Complex ◽  
Monogalactosyl Diglyceride ◽  
Prosthetic Groups ◽  
Β Carotene

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.

scholarly journals The structure of plant photosystem I super-complex at 2.8 Å resolution

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Yuval Mazor ◽  
Anna Borovikova ◽  
Nathan Nelson
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Photosystem I ◽  
Excitation Energy Transfer ◽  
Life Forms ◽  
Reaction Centers ◽  
Oxygenic Photosynthesis ◽  
Chlorophyll B ◽  
Higher Plant ◽  
Prosthetic Groups

Most life forms on Earth are supported by solar energy harnessed by oxygenic photosynthesis. In eukaryotes, photosynthesis is achieved by large membrane-embedded super-complexes, containing reaction centers and connected antennae. Here, we report the structure of the higher plant PSI-LHCI super-complex determined at 2.8 Å resolution. The structure includes 16 subunits and more than 200 prosthetic groups, which are mostly light harvesting pigments. The complete structures of the four LhcA subunits of LHCI include 52 chlorophyll a and 9 chlorophyll b molecules, as well as 10 carotenoids and 4 lipids. The structure of PSI-LHCI includes detailed protein pigments and pigment–pigment interactions, essential for the mechanism of excitation energy transfer and its modulation in one of nature's most efficient photochemical machines.

Crystal Forms of Semisynthetic Ergot Alkaloid Terguride

2002 ◽  
Vol 67 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Ladislav Cvak ◽  
Alexandr Jegorov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ergot Alkaloid ◽  
Simplified Model ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Crystal Forms ◽  
X Ray ◽  
Independent Molecules

Two new structures of semisynthetic ergot alkaloid terguride created by unusual number of symmetry-independent molecules were determined by X-ray diffraction methods at 150 K. Form A (monoclinic, P212121, Z = 12) contains three symmetry-independent terguride molecules and two molecules of water in the asymmetric part of the unit cell. The form CA (monoclinic, P21, Z = 8) is an anhydrate remarkable by the presence of four symmetry-independent molecules in the crystal structure. Conformations of twelve symmetry-independent molecules that were found in four already described terguride structures are compared with torsion angles obtained by ab initio quantum-mechanical calculations for the simplified model of N-cyclohexyl-N'-diethylurea.

Structure of plant photosystem I‐light harvesting complex I supercomplex at 2.4 Å resolution

2021 ◽  
Author(s):  
Jie Wang ◽  
Long‐Jiang Yu ◽  
Wenda Wang ◽  
Qiujing Yan ◽  
Tingyun Kuang ◽  
...  
Keyword(s):  
Photosystem I ◽  
Complex I ◽  
Light Harvesting ◽  
Light Harvesting Complex

Cloning of a pea cDNA encoding a polypeptide of the light-harvesting complex associated with photosystem I using a monoclonal antibody

1995 ◽  
Vol 27 (4) ◽  
pp. 821-824 ◽  
Author(s):  
Martin E. Cannell ◽  
Alison J. Mitchell ◽  
Sharon McCready ◽  
James A. Callow ◽  
Jonathan R. Green
Keyword(s):  
Monoclonal Antibody ◽  
Photosystem I ◽  
Light Harvesting ◽  
Light Harvesting Complex

scholarly journals Minimizing Polymorphic Risk Through Cooperative Computational and Experimental Exploration

2020 ◽  
Author(s):  
Christopher R. Taylor ◽  
Matthew T. Mulvee ◽  
Domonkos S. Perenyi ◽  
Michael R. Probert ◽  
Graeme Day ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Experimental Approach ◽  
Significant Risk ◽  
Free Energy Calculations ◽  
Crystal Structure Prediction ◽  
Crystal Forms ◽  
Wide Range ◽  
Solid Form

<div> <p>We combine state-of-the-art computational crystal structure prediction (CSP) techniques with a wide range of experimental crystallization methods to understand and explore crystal structure in pharmaceuticals and minimize the risk of unanticipated late-appearing polymorphs. Initially, we demonstrate the power of CSP to rationalize the difficulty in obtaining polymorphs of the well-known pharmaceutical isoniazid and show that CSP provides the structure of the recently discovered, but unsolved, Form III of this drug despite there being only a single known form for almost 70 years. More dramatically, our blind CSP study predicts a significant risk of polymorphism for the related iproniazid. Employing a wide variety of experimental techniques, including high-pressure experiments, we experimentally obtained the first three known non-solvated crystal forms of iproniazid, all of which were successfully predicted in the CSP procedure. We demonstrate the power of CSP methods and free energy calculations to rationalize the observed elusiveness of the third form of iproniazid, the success of high-pressure experiments in obtaining it, and the ability of our synergistic computational-experimental approach to “de-risk” solid form landscapes.</p> </div>

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