View source for 1ntk


==Crystal Structure of Mitochondrial Cytochrome bc1 in Complex with Antimycin A1==
<StructureSection load='1ntk' size='340' side='right'caption='[[1ntk]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ntk]] 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=1NTK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NTK 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]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=AY1:[(2R,3S,6S,7R,8R)-3-[(3-FORMAMIDO-2-OXIDANYL-PHENYL)CARBONYLAMINO]-8-HEXYL-2,6-DIMETHYL-4,9-BIS(OXIDANYLIDENE)-1,5-DIOXONAN-7-YL]+2-METHYLPROPANOATE'>AY1</scene>, <scene name='pdbligand=FES:FE2/S2+(INORGANIC)+CLUSTER'>FES</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=1ntk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ntk OCA], [https://pdbe.org/1ntk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ntk RCSB], [https://www.ebi.ac.uk/pdbsum/1ntk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ntk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/QCR1_BOVIN QCR1_BOVIN] This is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is part of the mitochondrial respiratory chain. This protein may mediate formation of the complex between cytochromes c and c1.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/nt/1ntk_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1ntk ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
Cytochrome bc(1) is an integral membrane protein complex essential to cellular respiration and photosynthesis. The Q cycle reaction mechanism of bc(1) postulates a separated quinone reduction (Q(i)) and quinol oxidation (Q(o)) site. In a complete catalytic cycle, a quinone molecule at the Q(i) site receives two electrons from the b(H) heme and two protons from the negative side of the membrane; this process is specifically inhibited by antimycin A and NQNO. The structures of bovine mitochondrial bc(1) in the presence or absence of bound substrate ubiquinone and with either the bound antimycin A(1) or NQNO were determined and refined. A ubiquinone with its first two isoprenoid repeats and an antimycin A(1) were identified in the Q(i) pocket of the substrate and inhibitor bound structures, respectively; the NQNO, on the other hand, was identified in both Q(i) and Q(o) pockets in the inhibitor complex. The two inhibitors occupied different portions of the Q(i) pocket and competed with substrate for binding. In the Q(o) pocket, the NQNO behaves similarly to stigmatellin, inducing an iron-sulfur protein conformational arrest. Extensive binding interactions and conformational adjustments of residues lining the Q(i) pocket provide a structural basis for the high affinity binding of antimycin A and for phenotypes of inhibitor resistance. A two-water-mediated ubiquinone protonation mechanism is proposed involving three Q(i) site residues His(201), Lys(227), and Asp(228).

Structural basis for the quinone reduction in the bc1 complex: a comparative analysis of crystal structures of mitochondrial cytochrome bc1 with bound substrate and inhibitors at the Qi site.,Gao X, Wen X, Esser L, Quinn B, Yu L, Yu CA, Xia D Biochemistry. 2003 Aug 5;42(30):9067-80. PMID:12885240<ref>PMID:12885240</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 1ntk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome C 3D structures|Cytochrome C 3D structures]]
*[[Cytochrome bc1 3D structures|Cytochrome bc1 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Esser L]]
[[Category: Gao X]]
[[Category: Quinn B]]
[[Category: Wen X]]
[[Category: Xia D]]
[[Category: Yu C-A]]
[[Category: Yu L]]