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1v54
From Proteopedia
(New page: 200px<br /><applet load="1v54" size="450" color="white" frame="true" align="right" spinBox="true" caption="1v54, resolution 1.8Å" /> '''Bovine heart cytochro...) |
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| - | [[Image:1v54.gif|left|200px]]<br /><applet load="1v54" size=" | + | [[Image:1v54.gif|left|200px]]<br /><applet load="1v54" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1v54, resolution 1.8Å" /> | caption="1v54, resolution 1.8Å" /> | ||
'''Bovine heart cytochrome c oxidase at the fully oxidized state'''<br /> | '''Bovine heart cytochrome c oxidase at the fully oxidized state'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Mitochondrial cytochrome c oxidase plays an essential role in aerobic | + | Mitochondrial cytochrome c oxidase plays an essential role in aerobic cellular respiration, reducing dioxygen to water in a process coupled with the pumping of protons across the mitochondrial inner membrane. An aspartate residue, Asp-51, located near the enzyme surface, undergoes a redox-coupled x-ray structural change, which is suggestive of a role for this residue in redox-driven proton pumping. However, functional or mechanistic evidence for the involvement of this residue in proton pumping has not yet been obtained. We report that the Asp-51 --> Asn mutation of the bovine enzyme abolishes its proton-pumping function without impairment of the dioxygen reduction activity. Improved x-ray structures (at 1.8/1.9-A resolution in the fully oxidized/reduced states) show that the net positive charge created upon oxidation of the low-spin heme of the enzyme drives the active proton transport from the interior of the mitochondria to Asp-51 across the enzyme via a water channel and a hydrogen-bond network, located in tandem, and that the enzyme reduction induces proton ejection from the aspartate to the mitochondrial exterior. A peptide bond in the hydrogen-bond network critically inhibits reverse proton transfer through the network. A redox-coupled change in the capacity of the water channel, induced by the hydroxyfarnesylethyl group of the low-spin heme, suggests that the channel functions as an effective proton-collecting region. Infrared results indicate that the conformation of Asp-51 is controlled only by the oxidation state of the low-spin heme. These results indicate that the low-spin heme drives the proton-pumping process. |
==About this Structure== | ==About this Structure== | ||
| - | 1V54 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with DMU, CU, MG, NA, ZN, HEA, CHD, CDL, TGL, PSC, PEK, PGV, CUA and UNX as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_oxidase Cytochrome-c oxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.9.3.1 1.9.3.1] Full crystallographic information is available from [http:// | + | 1V54 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=DMU:'>DMU</scene>, <scene name='pdbligand=CU:'>CU</scene>, <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=HEA:'>HEA</scene>, <scene name='pdbligand=CHD:'>CHD</scene>, <scene name='pdbligand=CDL:'>CDL</scene>, <scene name='pdbligand=TGL:'>TGL</scene>, <scene name='pdbligand=PSC:'>PSC</scene>, <scene name='pdbligand=PEK:'>PEK</scene>, <scene name='pdbligand=PGV:'>PGV</scene>, <scene name='pdbligand=CUA:'>CUA</scene> and <scene name='pdbligand=UNX:'>UNX</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_oxidase Cytochrome-c oxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.9.3.1 1.9.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V54 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:31:32 2008'' |
Revision as of 13:31, 21 February 2008
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Bovine heart cytochrome c oxidase at the fully oxidized state
Overview
Mitochondrial cytochrome c oxidase plays an essential role in aerobic cellular respiration, reducing dioxygen to water in a process coupled with the pumping of protons across the mitochondrial inner membrane. An aspartate residue, Asp-51, located near the enzyme surface, undergoes a redox-coupled x-ray structural change, which is suggestive of a role for this residue in redox-driven proton pumping. However, functional or mechanistic evidence for the involvement of this residue in proton pumping has not yet been obtained. We report that the Asp-51 --> Asn mutation of the bovine enzyme abolishes its proton-pumping function without impairment of the dioxygen reduction activity. Improved x-ray structures (at 1.8/1.9-A resolution in the fully oxidized/reduced states) show that the net positive charge created upon oxidation of the low-spin heme of the enzyme drives the active proton transport from the interior of the mitochondria to Asp-51 across the enzyme via a water channel and a hydrogen-bond network, located in tandem, and that the enzyme reduction induces proton ejection from the aspartate to the mitochondrial exterior. A peptide bond in the hydrogen-bond network critically inhibits reverse proton transfer through the network. A redox-coupled change in the capacity of the water channel, induced by the hydroxyfarnesylethyl group of the low-spin heme, suggests that the channel functions as an effective proton-collecting region. Infrared results indicate that the conformation of Asp-51 is controlled only by the oxidation state of the low-spin heme. These results indicate that the low-spin heme drives the proton-pumping process.
About this Structure
1V54 is a Protein complex structure of sequences from Bos taurus with , , , , , , , , , , , , and as ligands. Active as Cytochrome-c oxidase, with EC number 1.9.3.1 Full crystallographic information is available from OCA.
Reference
The low-spin heme of cytochrome c oxidase as the driving element of the proton-pumping process., Tsukihara T, Shimokata K, Katayama Y, Shimada H, Muramoto K, Aoyama H, Mochizuki M, Shinzawa-Itoh K, Yamashita E, Yao M, Ishimura Y, Yoshikawa S, Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15304-9. Epub 2003 Dec 12. PMID:14673090
Page seeded by OCA on Thu Feb 21 15:31:32 2008
Categories: Bos taurus | Cytochrome-c oxidase | Protein complex | Aoyama, H. | Ishimura, Y. | Katayama, Y. | Mochizuki, M. | Muramoto, K. | Shimada, H. | Shimokata, K. | Shinzawa-Itoh, K. | Tsukihara, T. | Yamashita, E. | Yao, M. | Yoshikawa, S. | CDL | CHD | CU | CUA | DMU | HEA | MG | NA | PEK | PGV | PSC | TGL | UNX | ZN | Oxidoreductase
