The acidic domain of cytochrome c1 in Paracoccus denitrificans, analogous to the acidic subunits in eukaryotic bc1 complexes, is not involved in the electron transfer reaction to its native substrate cytochrome c552

Castellani, Michela; Havens, Jeffrey; Kleinschroth, Thomas; Millett, Francis; Durham, Bill; Malatesta, Francesco; Ludwig, Bernd

doi:10.1016/j.bbabio.2011.08.001

Cited by 4 publications

(3 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kinetic analysis of cyt c 1CF mutants located near the heme crevice provided preliminary identification of the interaction site for cyt c 552F , and suggest that formation of the encounter complex is guided primarily by the overall electrostatic surface potential rather than by defined ion pairs [110]. Ruthenium kinetic studies have shown that the acidic domain does not play a significant role in the reaction of cyt c 552F with P. denitrificans cyt bc 1 [111]. The reaction between a ruthenium horse C c derivatve and R. sphaeroides cyt bc 1 was found to have an intracomplex rate constant of 60,000 s −1 [112].…”

Section: Reaction Between Cytochrome Bc1 and Cytochrome Cmentioning

confidence: 99%

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Millett

Havens

Rajagukguk

et al. 2013

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

The cytochrome bc1 complex (ubiquinone:cytochrome c oxidoreductase) is the central integral membrane protein in the mitochondrial respiratory chain as well as the electron-transfer chains of many respiratory and photosynthetic prokaryotes. Based on X-ray crystallographic studies of cytochrome bc1, a mechanism has been proposed in which the extrinsic domain of the iron-sulfur protein first binds to cytochrome b where it accepts an electron from ubiquinol in the Qo site, and then rotates by 57o to a position close to cytochrome c1 where it transfers an electron to cytochrome c1. This review describes the development of a ruthenium photooxidation technique to measure key electron transfer steps in cytochrome bc1, including rapid electron transfer from the iron-sulfur protein to cytochrome c1. It was discovered that this reaction is rate-limited by the rotational dynamics of the iron-sulfur protein rather than true electron transfer. A conformational linkage between the occupant of the Qo ubiquinol binding site and the rotational dynamics of the iron-sulfur protein was discovered which could play a role in the bifurcated oxidation of ubiquinol. A ruthenium photoexcitation method is also described for the measurement of electron transfer from cytochrome c1 to cytochrome c. This article is part of a special issue entitled: Respiratory Complex III.

show abstract

Section: Reaction Between Cytochrome Bc1 and Cytochrome Cmentioning

confidence: 99%

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Millett

Havens

Rajagukguk

et al. 2013

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Binding reduced QH 2 leads to release of reduced ISP from the b -state to the mobile state allowing electron transfer to cyt c 1 . The reaction of P. denitiricans cyt bc 1 with its native substrate cytochrome c 552 has been described in a recent publication (67). …”

Section: Discussionmentioning

confidence: 99%

“…The reaction of P. denitiricans cyt bc 1 with its native substrate cytochrome c 552 has been described in a recent publication. 67…”

Section: Biochemistrymentioning

confidence: 99%

Photoinitiated Electron Transfer within the Paracoccus denitrificans Cytochrome bc₁ Complex: Mobility of the Iron–Sulfur Protein Is Modulated by the Occupant of the Q_o Site

et al. 2011

Self Cite

View full text Add to dashboard Cite

Domain rotation of the Rieske iron-sulfur protein (ISP) between the cytochrome (cyt) b and cyt c1 redox centers plays a key role in the mechanism of the cyt bc1 complex. Electron transfer within the cyt bc1 complex of P. denitrificans was studied using a ruthenium dimer to rapidly photo-oxidize cyt c1 within 1 μs and initiate the reaction. In the absence of any added quinol or inhibitor of the bc1 complex at pH 8.0, electron transfer from reduced ISP to cyt c1 was biphasic with rate constants of k1f = 6300 ± 3000 s−1 and k1s = 640 ± 300 s−1 and amplitudes of 10 ± 3% and 16 ± 4 % of the total amount of cyt c1 photooxidized. Upon addition of any of the Pm type inhibitors MOA-stilbene, myxothiazol, or azoxystrobin to cyt bc1 in the absence of quinol, the total amplitude increased 2-fold, consistent with a decrease in redox potential of the ISP. In addition, the relative amplitude of the fast phase increased significantly, consistent with a change in the dynamics of the ISP domain rotation. In contrast, addition of the Pf type inhibitors JG-144 and famoxadone decreased the rate constant k1f by 5 to 10-fold, and increased the amplitude over 2-fold. Addition of quinol substrate in the absence of inhibitors led to a two-fold increase in the amplitude of the k1f phase. The effect of QH2 on the kinetics of electron transfer from reduced ISP to cyt c1 was thus similar to that of the Pm inhibitors and very different from that of the Pf inhibitors. The current results indicate that the species occupying the Qo site has a significant conformational influence on the dynamics of the ISP domain rotation.

show abstract

X-ray structure of the dimeric cytochrome bc1 complex from the soil bacterium Paracoccus denitrificans at 2.7-Å resolution

Kleinschroth

Castellani

Trinh

et al. 2011

Biochimica et Biophysica Acta (BBA) - Bioenergetics

View full text Add to dashboard Cite

The respiratory cytochrome bc(1) complex is a fundamental enzyme in biological energy conversion. It couples electron transfer from ubiquinol to cytochrome c with generation of proton motive force which fuels ATP synthesis. The complex from the α-proteobacterium Paracoccus denitrificans, a model for the medically relevant mitochondrial complexes, lacked structural characterization. We show by LILBID mass spectrometry that truncation of the organism-specific, acidic N-terminus of cytochrome c(1) changes the oligomerization state of the enzyme to a dimer. The fully functional complex was crystallized and the X-ray structure determined at 2.7-Å resolution. It has high structural homology to mitochondrial complexes and to the Rhodobacter sphaeroides complex especially for subunits cytochrome b and ISP. Species-specific binding of the inhibitor stigmatellin is noteworthy. Interestingly, cytochrome c(1) shows structural differences to the mitochondrial and even between the two Rhodobacteraceae complexes. The structural diversity in the cytochrome c(1) surface facing the ISP domain indicates low structural constraints on that surface for formation of a productive electron transfer complex. A similar position of the acidic N-terminal domains of cytochrome c(1) and yeast subunit QCR6p is suggested in support of a similar function. A model of the electron transfer complex with membrane-anchored cytochrome c(552), the natural substrate, shows that it can adopt the same orientation as the soluble substrate in the yeast complex. The full structural integrity of the P. denitrificans variant underpins previous mechanistic studies on intermonomer electron transfer and paves the way for using this model system to address open questions of structure/function relationships and inhibitor binding.

show abstract

The acidic domain of cytochrome c1 in Paracoccus denitrificans, analogous to the acidic subunits in eukaryotic bc1 complexes, is not involved in the electron transfer reaction to its native substrate cytochrome c552

Cited by 4 publications

References 42 publications

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Photoinitiated Electron Transfer within the Paracoccus denitrificans Cytochrome bc₁ Complex: Mobility of the Iron–Sulfur Protein Is Modulated by the Occupant of the Q_o Site

X-ray structure of the dimeric cytochrome bc1 complex from the soil bacterium Paracoccus denitrificans at 2.7-Å resolution

Contact Info

Product

Resources

About

The acidic domain of cytochrome c1 in Paracoccus denitrificans, analogous to the acidic subunits in eukaryotic bc1 complexes, is not involved in the electron transfer reaction to its native substrate cytochrome c552

Cited by 4 publications

References 42 publications

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c

Photoinitiated Electron Transfer within the Paracoccus denitrificans Cytochrome bc1 Complex: Mobility of the Iron–Sulfur Protein Is Modulated by the Occupant of the Qo Site

X-ray structure of the dimeric cytochrome bc1 complex from the soil bacterium Paracoccus denitrificans at 2.7-Å resolution

Contact Info

Product

Resources

About

Photoinitiated Electron Transfer within the Paracoccus denitrificans Cytochrome bc₁ Complex: Mobility of the Iron–Sulfur Protein Is Modulated by the Occupant of the Q_o Site