Binding of cyanide to cytochrome c′ from Chromatium vinosum

Kassner, Richard J.; Kykta, Michael G.; Cusanovich, Michael A.

doi:10.1016/0167-4838(85)90163-3

Cited by 33 publications

(26 citation statements)

References 24 publications

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“…It is reported that ligands, such as cyanide, nitric oxide, and carbon monoxide, are coordinated to the heme moiety, and change the E ′ of the proteins. [32][33][34] For example, the E ′ of horse heart cyt c changes from 260 to 220 mV vs. SHE by cyanide coordination. 35 In addition, it is confirmed that nitric oxide is coordinated to the OM cyt c of Shewanella.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Study on the Extracellular Electron Transfer Pathway from Shewanella Strain Hac319 to Electrodes

et al. 2018

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Shewanella can transfer electrons to various extracellular electron acceptors. We electrochemically investigated the pathway of extracellular electron transfer from Shewanella strain Hac319 to electrodes. A resting cell suspension of Shewanella strain Hac319 containing lactate produced a steady-state sigmoidal wave in the presence of flavin mononucleotide (FMN) in cyclic voltammetry, but not in the absence of FMN. A harvested cell suspension without cell-washing also produced a similar catalytic wave without any external addition of free FMN. The midpoint potentials of the two sigmoidal waves were identical to the redox potential of free FMN. The data indicate that FMN secreted from the Shewanella strain Hac319 works as an electron-transfer mediator from the cell to electrodes. An addition of cyanide to a resting cell suspension of Shewanella strain Hac319 increased the rate of the FMN reduction in the presence of lactate, while it decreased the respiration rate. By considering the fact that cyanide is coordinated to the heme moiety of hemoproteins and shifts the redox potential to the negative potential side, the data indicate that the electron derived from lactate is predominantly transferred in a down-hill mode from an electron donor with a redox potential more negative than that of FMN without going through outer membrane cytochromes c molecules.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Study on the Extracellular Electron Transfer Pathway from Shewanella Strain Hac319 to Electrodes

et al. 2018

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“…Cytochrome c ‘, found in photosynthetic bacteria, is a member of the family of electron transfer proteins where the heme (heme c ) is covalently bound to the peptide via thioether linkages to the Cys in the consensus sequence Cys-X-Y-Cys-His, with the His serving as the proximal axial ligand, , as shown in Figure . In contrast to the monomeric mitochondrial cytochromes c , where the linkage occurs near the N-terminus and which invariably are low-spin due to the distal ligation of Met, the usually dimeric cytochromes c ‘ have the linkage near the C-terminus and the iron is five-coordinate and, hence, predominately high-spin in both oxidation states. , The unusually low affinity for exogenous strong field ligands, , the variable cooperativity among different genetic variants, a p K in the physiological range that alters the redox properties, and the unusual proposed S = 5 / 2 , 3 / 2 spin-admixed ground state , have focused interest on the molecular structure of cytochromes c ‘. Crystal structures have been reported for Chromatium vinosum ( Cv ), , Rhodospirillum molischianum ( Rm ), , and Rhodospirillum rubrum ( Rr ) 14 cytochromes c ‘ which reveal similar dimeric structures with each polypeptide monomer folding into a four-helical bundle similar to that exhibited by cytochrome b 562 and the tobacco mosaic virus coat protein, among others.…”

Section: Introductionmentioning

confidence: 99%

An Interpretive Basis of the Proton Nuclear Magnetic Resonance Hyperfine Shifts for Structure Determination of High-Spin Ferric Hemoproteins. Implications for the Reversible Thermal Unfolding of Ferricytochromec‘ fromRhodopseudomonas palustris

et al. 1996

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An NMR approach to determining the solution molecular structure of a high-spin ferric hemoprotein, 13 kDa ferricytochrome c′ from Rhodopseudomonas palustris (Rp), has been investigated. In parallel with the use of appropriately tailored 1D and 2D experiments to provide scalar and dipolar correlations for the strongly relaxed and hyperfine-shifted heme cavity residues, we explore an interpretive basis of the large hyperfine shifts for noncoordinated residues which could provide constraints in solution structure determination for high-spin ferric hemoproteins. It is shown that the complete heme can be uniquely assigned in spite of the extreme relaxation properties (T 1 s 1-8 ms). Sufficient scalar connectivities are detected for strongly relaxed protons (T 1 g 4 ms) to uniquely assign residues on both the proximal and distal sides of the heme. The spatial correlations indicate that the structure is homologous to the four-helix bundle observed for other cytochromes c′. The pattern of large hyperfine shifts for noncoordinated residues is shown to be qualitatively reproduced by the dipolar shifts for a structural homolog based on an axial zero-field splitting of ∼12 cm -1 . It is concluded that, when this approach is combined with more conventional 2D methods for the diamagnetic portion of the protein, a complete structure determination of a five-coordinate ferric hemoprotein should be readily attainable. It is shown that the ferricytochrome c′ unfolds reversibly at high temperature and that there exists at least one equilibrium intermediate in this unfolding that is suggested to involve helix separation from the heme.

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“…Unexpectedly, the empty coordination site faces the interior of the protein and hence only small ligands (CO, NO, cyanide) bind to the iron. 3 The general features of the electronic absorption spectrum of the ferric state are typical of high-spin heme proteins. At neutral pH, however, the magnetic susceptibility is unusually low and a broad derivative-shaped feature is observed near g = 4 in the electron paramagnetic resonance (EPR)4 spectrum.5 In addition, a ligation-sensitive high-frequency resonance Raman mode is seen that is intermediate in energy between those observed for high-and low-spin ferric porphyrins.6 Mdssbauer studies of the ferric protein clearly indicate that only one magnetic species is present.7 Moss and Maltempo have proposed the existence of an intermediate-spin (S = 3/2) state with a quantum mechanical admixture of the more common high-spin (S = 5/2) state for the protein.8…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic studies of ferric porphyrins with quantum mechanically admixed intermediate-spin states: models for cytochrome c'

Kintner¹,

Dawson²

1991

Inorg. Chem.

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Binding of cyanide to cytochrome c′ from Chromatium vinosum

Cited by 33 publications

References 24 publications

Electrochemical Study on the Extracellular Electron Transfer Pathway from Shewanella Strain Hac319 to Electrodes

Electrochemical Study on the Extracellular Electron Transfer Pathway from Shewanella Strain Hac319 to Electrodes

An Interpretive Basis of the Proton Nuclear Magnetic Resonance Hyperfine Shifts for Structure Determination of High-Spin Ferric Hemoproteins. Implications for the Reversible Thermal Unfolding of Ferricytochromec‘ fromRhodopseudomonas palustris

Spectroscopic studies of ferric porphyrins with quantum mechanically admixed intermediate-spin states: models for cytochrome c'

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