View source for 4hea

==Crystal structure of the entire respiratory complex I from Thermus thermophilus==
<StructureSection load='4hea' size='340' side='right' caption='[[4hea]], [[Resolution|resolution]] 3.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4hea]] is a 32 chain structure with sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4HEA OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4HEA FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FES:FE2/S2+(INORGANIC)+CLUSTER'>FES</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4he8|4he8]]</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/NADH_dehydrogenase_(ubiquinone) NADH dehydrogenase (ubiquinone)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.5.3 1.6.5.3] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4hea FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4hea OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4hea RCSB], [http://www.ebi.ac.uk/pdbsum/4hea PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/NQO6_THET8 NQO6_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.[HAMAP-Rule:MF_01356] [[http://www.uniprot.org/uniprot/NQO3_THET8 NQO3_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. [[http://www.uniprot.org/uniprot/NQO9_THET8 NQO9_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 role of the nqo9 subunit appears to provide a 'connecting chain' of two clusters between cluster N5 and the terminal cluster N2, and to stabilize the structure of the complex by interacting with other subunits.[HAMAP-Rule:MF_01351] [[http://www.uniprot.org/uniprot/NQO2_THET8 NQO2_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. [[http://www.uniprot.org/uniprot/NQO15_THET8 NQO15_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 nqo15 subunit has probably a role in complex stabilization, and may be also involved in the storage of iron for iron-sulfur cluster regeneration in the complex.<ref>PMID:16469879</ref>  [[http://www.uniprot.org/uniprot/NQO4_THET8 NQO4_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 nqo4 subunit may contain the quinone-binding site.[HAMAP-Rule:MF_01358] [[http://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. [[http://www.uniprot.org/uniprot/NQO5_THET8 NQO5_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 nqo5 subunit may be involved in the stabilization of the complex.[HAMAP-Rule:MF_01357] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Complex I is the first and largest enzyme of the respiratory chain and has a central role in cellular energy production through the coupling of NADH:ubiquinone electron transfer to proton translocation. It is also implicated in many common human neurodegenerative diseases. Here, we report the first crystal structure of the entire, intact complex I (from Thermus thermophilus) at 3.3 A resolution. The structure of the 536-kDa complex comprises 16 different subunits, with a total of 64 transmembrane helices and 9 iron-sulphur clusters. The core fold of subunit Nqo8 (ND1 in humans) is, unexpectedly, similar to a half-channel of the antiporter-like subunits. Small subunits nearby form a linked second half-channel, which completes the fourth proton-translocation pathway (present in addition to the channels in three antiporter-like subunits). The quinone-binding site is unusually long, narrow and enclosed. The quinone headgroup binds at the deep end of this chamber, near iron-sulphur cluster N2. Notably, the chamber is linked to the fourth channel by a 'funnel' of charged residues. The link continues over the entire membrane domain as a flexible central axis of charged and polar residues, and probably has a leading role in the propagation of conformational changes, aided by coupling elements. The structure suggests that a unique, out-of-the-membrane quinone-reaction chamber enables the redox energy to drive concerted long-range conformational changes in the four antiporter-like domains, resulting in translocation of four protons per cycle.

Crystal structure of the entire respiratory complex I.,Baradaran R, Berrisford JM, Minhas GS, Sazanov LA Nature. 2013 Feb 28;494(7438):443-8. doi: 10.1038/nature11871. Epub 2013 Feb 17. PMID:23417064<ref>PMID:23417064</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Thermus thermophilus]]
[[Category: Baradaran, R]]
[[Category: Berrisford, J M]]
[[Category: Minhas, G S]]
[[Category: Sazanov, L A]]
[[Category: Complex i]]
[[Category: Cytoplasmic membrane]]
[[Category: Membrane protein]]
[[Category: Menaquinone]]
[[Category: Nadh]]
[[Category: Nadh-quinone oxidoreductase]]
[[Category: Oxidoreductase]]
[[Category: Proton pump]]