View source for 6hum


==Structure of the photosynthetic complex I from Thermosynechococcus elongatus==
<SX load='6hum' size='340' side='right' viewer='molstar' caption='[[6hum]], [[Resolution|resolution]] 3.34&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6hum]] is a 18 chain structure with sequence from [http://en.wikipedia.org/wiki/Thermosynechococcus_elongatus_bp-1 Thermosynechococcus elongatus bp-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HUM OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6HUM FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BCR:BETA-CAROTENE'>BCR</scene>, <scene name='pdbligand=LMG:1,2-DISTEAROYL-MONOGALACTOSYL-DIGLYCERIDE'>LMG</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6hum FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6hum OCA], [http://pdbe.org/6hum PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6hum RCSB], [http://www.ebi.ac.uk/pdbsum/6hum PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6hum ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/Q8DL30_THEEB Q8DL30_THEEB]] NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient.[RuleBase:RU004429] [[http://www.uniprot.org/uniprot/NDHK_THEEB NDHK_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration. [[http://www.uniprot.org/uniprot/NU4C1_THEEB NU4C1_THEEB]] NDH-1 shuttles electrons from NAD(P)H, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient.[HAMAP-Rule:MF_00491] [[http://www.uniprot.org/uniprot/NDHJ_THEEB NDHJ_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration. [[http://www.uniprot.org/uniprot/NDHH_THEEB NDHH_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration. [[http://www.uniprot.org/uniprot/NU3C_THEEB NU3C_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration (By similarity). [[http://www.uniprot.org/uniprot/NDHO_THEEB NDHO_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration (By similarity). [[http://www.uniprot.org/uniprot/NDHL_THEEB NDHL_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration (By similarity). [[http://www.uniprot.org/uniprot/NDHM_THEEB NDHM_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration (By similarity). [[http://www.uniprot.org/uniprot/NDHN_THEEB NDHN_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration (By similarity). [[http://www.uniprot.org/uniprot/Q8DL29_THEEB Q8DL29_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration.[HAMAP-Rule:MF_01456] [[http://www.uniprot.org/uniprot/NU1C_THEEB NU1C_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient.[HAMAP-Rule:MF_01350] [[http://www.uniprot.org/uniprot/NDHI_THEEB NDHI_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. [[http://www.uniprot.org/uniprot/NU2C_THEEB NU2C_THEEB]] NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient. Cyanobacterial NDH-1 also plays a role in inorganic carbon-concentration. 
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== Publication Abstract from PubMed ==
Photosynthetic complex I enables cyclic electron flow around photosystem I, a regulatory mechanism for photosynthetic energy conversion. We report a 3.3-A resolution cryo-EM structure of photosynthetic complex I from the cyanobacterium Thermosynechococcus elongatus. The model reveals structural adaptations that facilitate binding and electron transfer from the photosynthetic electron carrier ferredoxin. By mimicking cyclic electron flow with isolated components in vitro, we demonstrate that ferredoxin directly mediates electron transfer between photosystem I and complex I, instead of using intermediates such as NADPH. A large rate constant for association of ferredoxin to complex I indicates efficient recognition, with the protein subunit NdhS being the key component in this process.

Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer.,Schuller JM, Birrell JA, Tanaka H, Konuma T, Wulfhorst H, Cox N, Schuller SK, Thiemann J, Lubitz W, Setif P, Ikegami T, Engel BD, Kurisu G, Nowaczyk MM Science. 2018 Dec 20. pii: science.aau3613. doi: 10.1126/science.aau3613. PMID:30573545<ref>PMID:30573545</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6hum" style="background-color:#fffaf0;"></div>

==See Also==
*[[NADH-quinone oxidoreductase|NADH-quinone oxidoreductase]]
== References ==
<references/>
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</SX>
[[Category: Large Structures]]
[[Category: Thermosynechococcus elongatus bp-1]]
[[Category: Engel, B D]]
[[Category: Kurisu, G]]
[[Category: Nowaczyk, M M]]
[[Category: Schuller, J M]]
[[Category: Schuller, S K]]
[[Category: Complex i]]
[[Category: Cyclic electron flow]]
[[Category: Ferredoxin]]
[[Category: Membrane protein complex]]
[[Category: Proton transport]]
[[Category: Respiratory complex]]