View source for 9smi


==Reduced bovine complex I in lipid nanodisc, NADH-deactive==
<StructureSection load='9smi' size='340' side='right'caption='[[9smi]], [[Resolution|resolution]] 2.01&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9smi]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9SMI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9SMI 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]] 2.01&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=2MR:N3,+N4-DIMETHYLARGININE'>2MR</scene>, <scene name='pdbligand=3PE:1,2-DIACYL-SN-GLYCERO-3-PHOSPHOETHANOLAMINE'>3PE</scene>, <scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=ARO:C-GAMMA-HYDROXY+ARGININE'>ARO</scene>, <scene name='pdbligand=CDL:CARDIOLIPIN'>CDL</scene>, <scene name='pdbligand=CHD:CHOLIC+ACID'>CHD</scene>, <scene name='pdbligand=DGT:2-DEOXYGUANOSINE-5-TRIPHOSPHATE'>DGT</scene>, <scene name='pdbligand=EHZ:~{S}-[2-[3-[[(2~{R})-3,3-dimethyl-2-oxidanyl-4-phosphonooxy-butanoyl]amino]propanoylamino]ethyl]+(3~{S})-3-oxidanyltetradecanethioate'>EHZ</scene>, <scene name='pdbligand=FES:FE2/S2+(INORGANIC)+CLUSTER'>FES</scene>, <scene name='pdbligand=FME:N-FORMYLMETHIONINE'>FME</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=MYR:MYRISTIC+ACID'>MYR</scene>, <scene name='pdbligand=NAI:1,4-DIHYDRONICOTINAMIDE+ADENINE+DINUCLEOTIDE'>NAI</scene>, <scene name='pdbligand=NDP:NADPH+DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE+PHOSPHATE'>NDP</scene>, <scene name='pdbligand=PC1:1,2-DIACYL-SN-GLYCERO-3-PHOSPHOCHOLINE'>PC1</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=9smi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9smi OCA], [https://pdbe.org/9smi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9smi RCSB], [https://www.ebi.ac.uk/pdbsum/9smi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9smi ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Respiratory complex I is a multi-subunit energy-transducing membrane enzyme essential for mitochondrial and cellular energy metabolism. It couples NADH oxidation and ubiquinone-10 (Q(10)) reduction to the concomitant pumping of four protons to generate the proton-motive force that powers oxidative phosphorylation. Despite recent advances in structural knowledge of complex I, many mechanistic aspects including the reactive binding poses of Q(10), how Q(10) reduction initiates the proton transfer cascade, and how protons move through the membrane domain, remain unclear. Here, we use electron cryomicroscopy to determine structures of mammalian complex I, reconstituted into phospholipid nanodiscs containing exogenous Q(10) and reduced by NADH, to global resolutions of 2.0 to 2.6 A. Two conformations of a reduced Q(10)H(2) molecule are observed, fully inserted into the Q-binding channel in the turnover-relevant closed state. By comparing the quinone species bound in oxidised and reduced complex I structures, paired with molecular dynamics simulations to investigate the charge states of key surrounding residues, we propose a series of substrate binding poses that Q(10) transits through for reduction. Our highly hydrated structures exhibit near-continuous proton-transfer connections along the length of the membrane domain, enabling comparisons between them to assist in identifying the proton-transfer control points that are essential to catalysis.

Post-catalysis structures of mitochondrial complex I with ubiquinol-10 bound in the active site.,Chung I, Pereira CS, Wright JJ, Arantes GM, Hirst J Nat Commun. 2026 Mar 5. doi: 10.1038/s41467-026-70030-0. PMID:41786699<ref>PMID:41786699</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9smi" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Chung I]]
[[Category: Hirst J]]