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| {{STRUCTURE_1v54| PDB=1v54 | SCENE= }} | | {{STRUCTURE_1v54| PDB=1v54 | SCENE= }} |
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- | '''Bovine heart cytochrome c oxidase at the fully oxidized state'''
| + | ===Bovine heart cytochrome c oxidase at the fully oxidized state=== |
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- | ==Overview==
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- | 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.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_14673090}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 14673090 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_14673090}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Yoshikawa, S.]] | | [[Category: Yoshikawa, S.]] |
| [[Category: Oxidoreductase]] | | [[Category: Oxidoreductase]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 12:05:14 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 09:53:24 2008'' |
Revision as of 06:53, 29 July 2008
Template:STRUCTURE 1v54
Bovine heart cytochrome c oxidase at the fully oxidized state
Template:ABSTRACT PUBMED 14673090
About this Structure
1V54 is a Protein complex structure of sequences from Bos taurus. 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 Tue Jul 29 09:53:24 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. | Oxidoreductase