View source for 1v55

[[Image:1v55.gif|left|200px]]<br /><applet load="1v55" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1v55, resolution 1.9&Aring;" />
'''Bovine heart cytochrome c oxidase at the fully reduced state'''<br />

==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 --&gt; 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==
1V55 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=1V55 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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=14673090 14673090]
[[Category: Bos taurus]]
[[Category: Cytochrome-c oxidase]]
[[Category: Protein complex]]
[[Category: Aoyama, H.]]
[[Category: Ishimura, Y.]]
[[Category: Katayama, Y.]]
[[Category: Mochizuki, M.]]
[[Category: Muramoto, K.]]
[[Category: Shimada, H.]]
[[Category: Shimokata, K.]]
[[Category: Shinzawa-Itoh, K.]]
[[Category: Tsukihara, T.]]
[[Category: Yamashita, E.]]
[[Category: Yao, M.]]
[[Category: Yoshikawa, S.]]
[[Category: CDL]]
[[Category: CHD]]
[[Category: CU]]
[[Category: CUA]]
[[Category: DMU]]
[[Category: HEA]]
[[Category: MG]]
[[Category: NA]]
[[Category: PEK]]
[[Category: PGV]]
[[Category: PSC]]
[[Category: TGL]]
[[Category: UNX]]
[[Category: ZN]]
[[Category: oxidoreductase]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:31:38 2008''