Structure and function of a molecular machine: cytochrome c oxidase

Malatesta, Francesco; Antonini, Giovanni; Sarti, Paolo; Brunori, Maurizio

doi:10.1016/0301-4622(94)00117-3

Cited by 102 publications

(110 citation statements)

References 196 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…On the other hand, the calculated spectrum B for the species b is the same as that of the 10-ns photoproduct of MVCO reported by Proshlyakov et al (23), confirming the authenticity of this spectrum for species b. In addition, the consistency of these two spectra indicates that at 10 ns, the CO has already been cleaved from heme a 3 and that the initial electron transfer from heme a 3 to heme a takes longer than 10 ns. Based on this conclusion, we exclude the possibility for the existence of the ultrafast electron tunneling phase with a rate of Ն10 8 s Ϫ1 reported by Verkhovsky et al (16).…”

Section: Electron Redistribution In Cytochrome C Oxidasesupporting

confidence: 85%

“…Progressive spectral changes in several of the modes are evident: 1) the decrease in the intensity of the electron density marker line ( 4 ) of the CO bound heme a 3 2ϩ at 1368 cm Ϫ1 ; 2) the increase in intensity of the high spin marker line ( 2 ) at 1570 cm Ϫ1 of the ligand-free heme a 3 2ϩ ; and 3) the decrease in the intensity of the reduced heme a 3 formyl line at 1667 cm Ϫ1 . These changes reflect the photodissociation of CO from heme a 3 and its conversion to a ferric heme due to the subsequent electron transfer to heme a. The electron transfer from heme a 3 SCHEME 1…”

Section: Resultsmentioning

confidence: 99%

“…We propose that the single electron in the binuclear center in species c and d is delocalized on heme a 3 and Cu B as reflected by the equilibrium between c and cЈ and that between d and dЈ. Electron delocalization in heme a 3 and Cu B in the binuclear center is not unprecedented. It has been reported in the past that the electrons can reside on heme a, heme a 3 , or the Cu B site when CcO is not fully reduced (25)(26)(27)(28)(29)(30).…”

Section: Electron Redistribution In Cytochrome C Oxidasementioning

confidence: 90%

“…Under physiological conditions, the electron donor, cytochrome c, donates electrons to Cu A , which is located near the cytochrome c binding site. The electrons in Cu A are subsequently transferred to heme a and then to the binuclear center consisting of heme a 3 and Cu B , where oxygen reduction occurs (1)(2)(3)(4). It requires four electrons for one molecule of oxygen to be reduced to two molecules of water.…”

mentioning

confidence: 99%

“…The MVCO species is a two-electron reduced derivative in which heme a 3 and Cu B are reduced, whereas the other two redox centers, heme a and Cu A , remain oxidized. The reduced state of the binuclear center in MVCO is stabilized by a CO molecule bound to the iron atom of heme a 3 .…”

mentioning

confidence: 99%

See 4 more Smart Citations

Modulation of the Electron Redistribution in Mixed Valence Cytochrome c Oxidase by Protein Conformational Changes

Yeh

Rousseau

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

The redistribution of two electrons in the four redox centers of cytochrome c oxidase following photodissociation of CO from the CO-bound mixed valence species has been examined by resonance Raman spectroscopy. To account for both the kinetic data, obtained from 5 s to 2 ms, and the equilibrium results, a model is proposed in which the electron redistribution is modulated by a protein conformation transition from a nascent P 1 state to a relaxed P 2 state in a time window longer than 2 ms. In this model, all six possible two-electron reduced species are considered. The high population of species with a one-electron reduced binuclear center, in which the spectrum of heme a 3 is perturbed by the redox state of Cu B , accounts for the significant residuals in the fitting of the kinetic data with four standard spectra derived from redox species with either zero or two electrons in the binuclear center. Under equilibrium conditions, the conformational change to the P 2 state destabilizes the redox states with only one electron in the binuclear center with respect to those with either zero or two electrons. As a result, the redox equilibrium is perturbed, and the electrons are redistributed. A simulation based on the new kinetics scheme, in which the electron redistribution is modulated by the protein conformation, gives reasonable agreement with both the equilibrium and the kinetic data, demonstrating the validity of this model.

show abstract

Section: Electron Redistribution In Cytochrome C Oxidasesupporting

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: Electron Redistribution In Cytochrome C Oxidasementioning

confidence: 90%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Modulation of the Electron Redistribution in Mixed Valence Cytochrome c Oxidase by Protein Conformational Changes

Yeh

Rousseau

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

Oxygen and proton pathways in cytochrome c oxidase

1998

View full text Add to dashboard Cite

Cytochrome c oxidase is a redox-driven proton pump, which couples the reduction of oxygen to water to the translocation of protons across the membrane. The recently solved x-ray structures of cytochrome c oxidase permit molecular dynamics simulations of the underlying transport processes. To eventually establish the proton pump mechanism, we investigate the transport of the substrates, oxygen and protons, through the enzyme. Molecular dynamics simulations of oxygen diffusion through the protein reveal a well-defined pathway to the oxygen-binding site starting at a hydrophobic cavity near the membrane-exposed surface of subunit I, close to the interface to subunit III. A large number of water sites are predicted within the protein, which could play an essential role for the transfer of protons in cytochrome c oxidase. The water molecules form two channels along which protons can enter from the cytoplasmic (matrix) side of the protein and reach the binuclear center. A possible pumping mechanism is proposed that involves a shuttling motion of a glutamic acid side chain, which could then transfer a proton to a propionate group of heme alpha 3.

show abstract

Wasserlösliche dendritische Eisenporphyrine: synthetische Modelle für globuläre Häm‐Proteine

et al. 1995

View full text Add to dashboard Cite

Drastisch unterscheidet sich das Redoxverhalten der Verbindung 1, eines Dendrimers der zweiten Generation, von dem des entsprechendem Dendrimers der ersten Generation, das keine dicht gepackte dendritische Umhüllung aufweist. Das ungewöhnlich positive FeIII/FeII‐Redoxpotential (+ 0.19 V vs. SCE) von 1 in Wasser wird auf die starke Abschirmung des Häm‐Kernes vom externen Lösungsmittel durch die dendritische Hülle zurückgeführt .

show abstract

Structure and function of a molecular machine: cytochrome c oxidase

Cited by 102 publications

References 196 publications

Modulation of the Electron Redistribution in Mixed Valence Cytochrome c Oxidase by Protein Conformational Changes

Modulation of the Electron Redistribution in Mixed Valence Cytochrome c Oxidase by Protein Conformational Changes

Oxygen and proton pathways in cytochrome c oxidase

Wasserlösliche dendritische Eisenporphyrine: synthetische Modelle für globuläre Häm‐Proteine

Contact Info

Product

Resources

About