The pH dependence of cytochrome a conformation in cytochrome c oxidase.

Ishibe, N; Lynch, Stephen R.; Copeland, Robert A.

doi:10.1016/s0021-9258(18)54371-4

Cited by 14 publications

(21 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present investigation, the spectra of cytochrome c oxidase purified from beef heart and from P. denitrificans were studied with the goal of further characterizing the doublet features detected in the second derivative absorption spectrum of cytochrome a (Copeland, 1991(Copeland, , 1993Ishibe et al, 1991;Sherman et al, 1991;Lynch et al, 1992;Felsch et al, 1994). In earlier studies of intact mitochondria, collection of difference spectral data was necessary to suppress the absorption contributions of other cytochromes present in mitochondria and the light-scattering contributions from mitochondrial particles (Wilson and Gilmour, 1967;Wikström et al, 1976).…”

Section: The Two-component Absorption Spectrum Of Cytochrome Amentioning

confidence: 99%

“…Since the electronic structure of the heme prosthetic groups may be sensitive to perturbations from the protein, conformational states involved in coupling electron transfer and proton translocation may be distinguishable by electronic absorption spectroscopy. Because there is extensive overlap in the spectra of the heme A and heme A 3 groups (Vanneste, 1966), second derivative absorption spectroscopy (Williams and Hager, 1970;Cahill, 1979) has been applied to cytochrome c oxidase to separate their characteristic features (Copeland, 1991(Copeland, , 1993Ishibe et al, 1991;Sherman et al, 1991;Lynch et al, 1992;Felsch et al, 1994). The initial report of second derivative absorption spectra of cytochrome c oxidase showed a feature at 450 nm for ligandbound forms of the enzyme that was not resolved in spectra of unliganded (reduced) cytochrome c oxidase, while the unliganded enzyme was associated with a feature at 440 nm (Sherman et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Horvath

Copeland

Makinen

1999

Biophysical Journal

View full text Add to dashboard Cite

The electronic absorption spectrum of solubilized beef heart cytochrome c oxidase was analyzed in the 400-500 nm region to identify the origin of doublet features appearing in the second derivative spectrum associated with ferrocytochrome a. This doublet, centered near 22,600 cm(-1), was observed in the direct absorption spectrum of the a(2+)a(3)(3+).HCOO(-) form of the enzyme at cryogenic temperatures. Since evidence for this doublet at room temperature is obtained only on the basis of the second derivative spectrum, a novel mathematical approach was developed to analyze the resolving power of second derivative spectroscopy as a function of parameterization of spectral data. Within the mathematical limits defined for resolving spectral features, it was demonstrated that the integrated intensity of the doublet feature near 450 nm associated with ferrocytochrome a is independent of the ligand and oxidation state of cytochrome a(3). Furthermore, the doublet features, also observed in cytochrome c oxidase from Paracoccus denitrificans, were similarly associated with the heme A component and were correspondingly independent of the ligand and oxidation state of the heme A(3) chromophore. The doublet features are attributed to lifting of the degeneracy of the x and y polarized components of the B state of the heme A chromophore associated with the Soret transition.

show abstract

Section: The Two-component Absorption Spectrum Of Cytochrome Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Horvath

Copeland

Makinen

1999

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…The ratio of 440 nm to 450 nm band intensities of reduced cytochrome a in CN-bound oxidase has been found previously to be dependent on the pH of the solution and also on the interaction with cytochrome c. 23,25,26 The effects of pH and cytochrome c on the spectroscopic properties of heme a were developed slowly (∼30 min) during the incubation under an anaerobic atmosphere.…”

Section: ■ Resultsmentioning

confidence: 82%

“…34 Interestingly, these two electronic transitions of the reduced cytochrome a exhibited a sensitivity to certain physiological conditions. The relative intensity of this doublet was substantially affected by the pH of the solution, 23 the interaction with cytochrome c, 26 and also the steady-state turnover of CcO. 22 These studies indicated the possible cycling of the protein environment of cytochrome a between two states, one associated with the transition at 444 nm and the other characterized by the 450 nm Soret band.…”

mentioning

confidence: 95%

Response of Heme Symmetry to the Redox State of Bovine Cytochrome c Oxidase

et al. 2018

View full text Add to dashboard Cite

Second-derivative absorption spectroscopy was employed to monitor the response of effective symmetry of cytochromes a and a to the redox and ligation states of bovine cytochrome c oxidase (CcO). The Soret band π → π* electronic transitions were used to display the changes in symmetry of these chromophores induced by the reduction of CcO inhibited by the exogenous ligands and during catalytic turnover. The second derivative of the difference absorption spectra revealed only a single Soret band for the oxidized cytochromes a and a and cyanide-ligated oxidized cytochrome a. In contrast, two absorption bands were resolved in ferrous cytochrome a and ferrous cytochrome a ligated with cyanide. A transition from one-band spectrum to two-band spectrum indicates the lowering of symmetry of these hemes due to the alteration of their immediate surroundings. It is suggested that the changes in polarity occurring in the vicinity of these cofactors are main reason for the split of the Soret band of both ferrous cytochrome a and cyanide-bound ferrous cytochrome a.

show abstract

“…Hence, cholate not only disrupts the original supercomplex formation of the ETC but may also hinder the subsequent electron transfer rate as shown in different kinetic measurements of the enzymatic activity. Moreover, an influence of a pH shift cannot be neglected because it also effects the dimeric/monomeric ratio [ 37 , 58 ]. Interestingly, our experimental findings of an increase in specific activity of CytOx at 0.1 and 1% cholate are in accordance with the studies of late 1970s [ 59 ].…”

Section: Discussionmentioning

confidence: 99%

Cholate Disrupts Regulatory Functions of Cytochrome c Oxidase

Ramzan

Napiwotzki²,

Weber

et al. 2021

Cells

View full text Add to dashboard Cite

Cytochrome c oxidase (CytOx), the oxygen-accepting and rate-limiting enzyme of mitochondrial respiration, binds with 10 molecules of ADP, 7 of which are exchanged by ATP at high ATP/ADP-ratios. These bound ATP and ADP can be exchanged by cholate, which is generally used for the purification of CytOx. Many crystal structures of isolated CytOx were performed with the enzyme isolated from mitochondria using sodium cholate as a detergent. Cholate, however, dimerizes the enzyme isolated in non-ionic detergents and induces a structural change as evident from a spectral change. Consequently, it turns off the “allosteric ATP-inhibition of CytOx”, which is reversibly switched on under relaxed conditions via cAMP-dependent phosphorylation and keeps the membrane potential and ROS formation in mitochondria at low levels. This cholate effect gives an insight into the structural-functional relationship of the enzyme with respect to ATP inhibition and its role in mitochondrial respiration and energy production.

show abstract

The pH dependence of cytochrome a conformation in cytochrome c oxidase.

Cited by 14 publications

References 24 publications

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

The Second Derivative Electronic Absorption Spectrum of Cytochrome c Oxidase in the Soret Region

Response of Heme Symmetry to the Redox State of Bovine Cytochrome c Oxidase

Cholate Disrupts Regulatory Functions of Cytochrome c Oxidase

Contact Info

Product

Resources

About