View source for 6q8o


==Respiratory complex I from Thermus thermophilus with bound Piericidin A==
<StructureSection load='6q8o' size='340' side='right'caption='[[6q8o]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6q8o]] is a 20 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB8 Thermus thermophilus HB8]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6Q8O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6Q8O FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.605&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FES:FE2/S2+(INORGANIC)+CLUSTER'>FES</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</scene>, <scene name='pdbligand=HQH:2,3-dimethoxy-5-methyl-6-[(2~{E},5~{E},7~{E},9~{R},10~{R},11~{E})-3,7,9,11-tetramethyl-10-oxidanyl-trideca-2,5,7,11-tetraenyl]-1~{H}-pyridin-4-one'>HQH</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=6q8o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6q8o OCA], [https://pdbe.org/6q8o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6q8o RCSB], [https://www.ebi.ac.uk/pdbsum/6q8o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6q8o ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NQO1_THET8 NQO1_THET8] NDH-1 shuttles electrons from NADH, 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 menaquinone. 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 required for the synthesis of ATP. The nqo1 subunit contains the NADH-binding site and the primary electron acceptor FMN.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Complex I is the first and the largest enzyme of respiratory chains in bacteria and mitochondria. The mechanism which couples spatially separated transfer of electrons to proton translocation in complex I is not known. Here we report five crystal structures of T. thermophilus enzyme in complex with NADH or quinone-like compounds. We also determined cryo-EM structures of major and minor native states of the complex, differing in the position of the peripheral arm. Crystal structures show that binding of quinone-like compounds (but not of NADH) leads to a related global conformational change, accompanied by local re-arrangements propagating from the quinone site to the nearest proton channel. Normal mode and molecular dynamics analyses indicate that these are likely to represent the first steps in the proton translocation mechanism. Our results suggest that quinone binding and chemistry play a key role in the coupling mechanism of complex I.

Key role of quinone in the mechanism of respiratory complex I.,Gutierrez-Fernandez J, Kaszuba K, Minhas GS, Baradaran R, Tambalo M, Gallagher DT, Sazanov LA Nat Commun. 2020 Aug 18;11(1):4135. doi: 10.1038/s41467-020-17957-0. PMID:32811817<ref>PMID:32811817</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6q8o" style="background-color:#fffaf0;"></div>

==See Also==
*[[NADH-quinone oxidoreductase|NADH-quinone oxidoreductase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus thermophilus HB8]]
[[Category: Gutierrez-Fernandez J]]
[[Category: Minhas GS]]
[[Category: Sazanov LA]]