View source for 5zgh


==Cryo-EM structure of the red algal PSI-LHCR==
<SX load='5zgh' size='340' side='right' viewer='molstar' caption='[[5zgh]], [[Resolution|resolution]] 3.82&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5zgh]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Cyanidioschyzon_merolae_strain_10D Cyanidioschyzon merolae strain 10D]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ZGH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5ZGH FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.82&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=1DO:1-DODECANOL'>1DO</scene>, <scene name='pdbligand=3XQ:(2S)-2,3-dihydroxypropyl+octadecanoate'>3XQ</scene>, <scene name='pdbligand=BCR:BETA-CAROTENE'>BCR</scene>, <scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=CLA:CHLOROPHYLL+A'>CLA</scene>, <scene name='pdbligand=DGD:DIGALACTOSYL+DIACYL+GLYCEROL+(DGDG)'>DGD</scene>, <scene name='pdbligand=LHG:1,2-DIPALMITOYL-PHOSPHATIDYL-GLYCEROLE'>LHG</scene>, <scene name='pdbligand=PQN:PHYLLOQUINONE'>PQN</scene>, <scene name='pdbligand=ZEX:(3S,5R,6S,3S,5R,6S)+BETA-CAROTENE-3,23-DIOL'>ZEX</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5zgh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5zgh OCA], [https://pdbe.org/5zgh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5zgh RCSB], [https://www.ebi.ac.uk/pdbsum/5zgh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5zgh ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q85FZ1_CYAM1 Q85FZ1_CYAM1] 
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== Publication Abstract from PubMed ==
Photosystem I (PSI) is one of the two photosystems present in oxygenic photosynthetic organisms and functions to harvest and convert light energy into chemical energy in photosynthesis. In eukaryotic algae and higher plants, PSI consists of a core surrounded by variable species and numbers of light-harvesting complex (LHC)I proteins, forming a PSI-LHCI supercomplex. Here, we report cryo-EM structures of PSI-LHCR from the red alga Cyanidioschyzon merolae in two forms, one with three Lhcr subunits attached to the side, similar to that of higher plants, and the other with two additional Lhcr subunits attached to the opposite side, indicating an ancient form of PSI-LHCI. Furthermore, the red algal PSI core showed features of both cyanobacterial and higher plant PSI, suggesting an intermediate type during evolution from prokaryotes to eukaryotes. The structure of PsaO, existing in eukaryotic organisms, was identified in the PSI core and binds three chlorophylls a and may be important in harvesting energy and in mediating energy transfer from LHCII to the PSI core under state-2 conditions. Individual attaching sites of LHCRs with the core subunits were identified, and each Lhcr was found to contain 11 to 13 chlorophylls a and 5 zeaxanthins, which are apparently different from those of LHCs in plant PSI-LHCI. Together, our results reveal unique energy transfer pathways different from those of higher plant PSI-LHCI, its adaptation to the changing environment, and the possible changes of PSI-LHCI during evolution from prokaryotes to eukaryotes.

Unique organization of photosystem I-light-harvesting supercomplex revealed by cryo-EM from a red alga.,Pi X, Tian L, Dai HE, Qin X, Cheng L, Kuang T, Sui SF, Shen JR Proc Natl Acad Sci U S A. 2018 Apr 9. pii: 1722482115. doi:, 10.1073/pnas.1722482115. PMID:29632169<ref>PMID:29632169</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 5zgh" style="background-color:#fffaf0;"></div>

==See Also==
*[[Photosystem I 3D structures|Photosystem I 3D structures]]
== References ==
<references/>
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[[Category: Cyanidioschyzon merolae strain 10D]]
[[Category: Large Structures]]
[[Category: Pi X]]