View source for 6juw


==BOVINE HEART CYTOCHROME C OXIDASE IN CATALITIC INTERMEDIATES AT 1.80 ANGSTROM RESOLUTION==
<StructureSection load='6juw' size='340' side='right'caption='[[6juw]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6juw]] is a 20 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=6JUW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6JUW 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CDL:CARDIOLIPIN'>CDL</scene>, <scene name='pdbligand=CHD:CHOLIC+ACID'>CHD</scene>, <scene name='pdbligand=CU:COPPER+(II)+ION'>CU</scene>, <scene name='pdbligand=CUA:DINUCLEAR+COPPER+ION'>CUA</scene>, <scene name='pdbligand=DMU:DECYL-BETA-D-MALTOPYRANOSIDE'>DMU</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=FME:N-FORMYLMETHIONINE'>FME</scene>, <scene name='pdbligand=HEA:HEME-A'>HEA</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=PEK:(1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(STEAROYLOXY)METHYL]ETHYL+(5E,8E,11E,14E)-ICOSA-5,8,11,14-TETRAENOATE'>PEK</scene>, <scene name='pdbligand=PGV:(1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL+(11E)-OCTADEC-11-ENOATE'>PGV</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=PSC:(7R,17E,20E)-4-HYDROXY-N,N,N-TRIMETHYL-9-OXO-7-[(PALMITOYLOXY)METHYL]-3,5,8-TRIOXA-4-PHOSPHAHEXACOSA-17,20-DIEN-1-AMINIUM+4-OXIDE'>PSC</scene>, <scene name='pdbligand=SAC:N-ACETYL-SERINE'>SAC</scene>, <scene name='pdbligand=TGL:TRISTEAROYLGLYCEROL'>TGL</scene>, <scene name='pdbligand=TPO:PHOSPHOTHREONINE'>TPO</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=6juw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6juw OCA], [https://pdbe.org/6juw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6juw RCSB], [https://www.ebi.ac.uk/pdbsum/6juw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6juw ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/COX1_BOVIN COX1_BOVIN] Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Subunits 1-3 form the functional core of the enzyme complex. CO I is the catalytic subunit of the enzyme. Electrons originating in cytochrome c are transferred via the copper A center of subunit 2 and heme A of subunit 1 to the bimetallic center formed by heme A3 and copper B.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cytochrome c oxidase (CcO) reduces O2 to water, coupled with a proton-pumping process. The structure of the O2-reduction site of CcO contains two reducing equivalents, Fe a3 (2+) and CuB (1+), and suggests that a peroxide-bound state (Fe a3 (3+)-O(-)-O(-)-CuB (2+)) rather than an O2-bound state (Fe a3 (2+)-O2) is the initial catalytic intermediate. Unexpectedly, however, resonance Raman spectroscopy results have shown that the initial intermediate is Fe a3 (2+)-O(2), whereas Fe a3 (3+)-O(-)-O(-)-CuB (2+) is undetectable. Based on X-ray structures of static non-catalytic CcO forms and mutation analyses for bovine CcO, a proton-pumping mechanism has been proposed. It involves a proton-conducting pathway (the H-pathway) comprising a tandem hydrogen-bond network and a water channel located between the N and P side surfaces. However, a system for unidirectional proton-transport has not been experimentally identified. Here, an essentially identical X-ray structure for the two catalytic intermediates (P and F) of bovine CcO was determined at 1.8 A resolution. A 1.70 A Fe-O distance of the ferryl center could be best described as Fe a3 (4+)=O(2-), not as Fe a3 (4+)-OH(-) The distance suggests a ~800 cm(-1) Raman stretching band. We found an interstitial water molecule which could trigger a rapid proton-coupled electron transfer from tyrosine-OH to the slowly forming Fe a3 (3+)-O(-)-O(-)-CuB (2+) state, preventing its detection, consistent with the unexpected Raman results. The H-pathway structures of both intermediates indicated that during proton-pumping from the hydrogen-bond network to the P-side, a transmembrane helix closes the water channel connecting the N-side with the hydrogen-bond network, facilitating unidirectional proton-pumping during the P-to-F transition.

X-ray structures of catalytic intermediates of cytochrome c oxidase provide insights into its O2-activation and unidirectional proton-pump mechanisms.,Shimada A, Etoh Y, Kitoh-Fujisawa R, Sasaki A, Shinzawa-Itoh K, Hiromoto T, Yamashita E, Muramoto K, Tsukihara T, Yoshikawa S J Biol Chem. 2020 Mar 12. pii: RA119.009596. doi: 10.1074/jbc.RA119.009596. PMID:32165497<ref>PMID:32165497</ref>

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

==See Also==
*[[Cytochrome c oxidase 3D structures|Cytochrome c oxidase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Muramoto K]]
[[Category: Shimada A]]
[[Category: Shinzawa-Itoh K]]
[[Category: Tsukihara T]]
[[Category: Yoshikawa S]]