Oxidation State-Induced Change of Iron Ligand in the Phenylalanine-82 to Histidine Mutant of Yeast Iso-1-cytochrome <i>c</i>

Schejter, Abel; Taler, Galia; Liu, Xiangjun; Margoliash, E.

doi:10.1021/ja9529448

Cited by 18 publications

(25 citation statements)

References 10 publications

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“…24 The band at 262 nm in the CD spectrum of reduced F82H suggests the presence of the same linkage to the heme iron in this protein. This result is consistent with that obtained using NMR 17 and magnetically induced CD 16 techniques. The differences in the heme environment in WT cytochrome c and F82H mutant in both reduced and oxidized forms is difficult to ascertain in detail from the intrinsic CD spectra.…”

Section: Uv-vis and CD Spectrasupporting

confidence: 91%

“…A small change in the global structure of the protein upon the ligand substitution was also confirmed by a fluorometric titration. 17 The intrinsic CD spectra of the reduced WT and F82H are shown in Figure 3. With respect to 209-and 222-nm bands, a similar trend was observed in the reduced form.…”

Section: Uv-vis and CD Spectramentioning

confidence: 99%

“…Using near-IR magnetic circular dichroism (CD) and NMR, it was demonstrated that in the oxidized mutant the histidine serves as the sixth coordination ligand to the iron instead of methionine (Met), despite the fact that the latter amino acid is still present at position 80. 16,17 This is a unique example of the change in the heme iron coordination structure achieved through site-directed mutagenesis in which the original amino acid ligand is not removed.…”

Section: Introductionmentioning

confidence: 99%

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Circular dichroism and resonance Raman comparative studies of wild type cytochrome c and F82H mutant

Zheng¹,

Ye²,

Lu³

et al. 2000

Biopolymers

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The UV-visible, circular dichroism (CD), and resonance Raman (RR) spectra of the wild type yeast iso-1-cytochrome c (WT) and its mutant F82H in which phenylalanine-82 (Phe-82) is substituted with His are measured and compared for oxidized and reduced forms. The CD spectra in the intrinsic and Soret spectral region, as well as RR spectra in high, middle, and low frequency regions, are discussed. From the analysis of the spectra, it is determined that in the oxidized F82H the two axial ligands to the heme iron are His-18 and His-82 whereas in the reduced form the sixth ligand switches from His-82 to Met-80 providing the coordination geometry similar to that of WT. Based on the spectroscopic data, the conclusion is that the porphyrin macrocycle is less distorted in the oxidized F82H compared to the oxidized WT. Similar distortions are present in the reduced form of the proteins. Frequency shifts of Raman bands, as well as the decrease of the alpha-helix content in the CD spectra, indicate more open conformation of the protein around the heme.

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Section: Uv-vis and CD Spectrasupporting

confidence: 91%

Section: Uv-vis and CD Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Circular dichroism and resonance Raman comparative studies of wild type cytochrome c and F82H mutant

Zheng¹,

Ye²,

Lu³

et al. 2000

Biopolymers

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“…Another example of a redox-driven heme-ligand switching event has been reported for the yeast F82H/C102S iso-1-cytochrome c variant (7,8). In the reduced state of the protein, the heme iron is coordinated by His 18 and Met 80 , similar to the wild-type protein, whereas the heme iron is ligated by His 18 and His 82 in the oxidized protein.…”

Section: -Met 106 Ligation Similar To Reduced C Domains This Form Imentioning

confidence: 92%

Heme Ligation and Conformational Plasticity in the Isolatedc Domain of Cytochrome cd 1 Nitrite Reductase

Steensma

Gordon

Öster

et al. 2001

Journal of Biological Chemistry

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“…Another demonstration that reduction increases the affinity of the heme iron for a methionyl sulfur is the fact that substitution of histidine for the Phe 82 in iso‐1 cyt c results in the displacement of Met 80 from the ferric iron by the new residue (Hawkins et al 1994). However, upon reduction of the metal, the normal Met 80 –Fe 2+ bond is restored (Schejter et al 1996; Feinberg et al 1998). For comparison, in Met‐65,80‐dicarboxymethyl cyt c , a chemically modified cyt c in which the alkylated Met 80 sulfur is displaced from the iron, the reduced metal binds oxygen rapidly and is oxidized to the ferric state within a few minutes (Schejter and Aviram 1970).…”

Section: Discussionmentioning

confidence: 99%

The redox couple of the cytochrome c cyanide complex: The contribution of heme iron ligation to the structural stability, chemical reactivity, and physiological behavior of horse cytochrome c

Schejter

2006

Protein Science

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Contrary to most heme proteins, ferrous cytochrome c does not bind ligands such as cyanide and CO. In order to quantify this observation, the redox potential of the ferric/ferrous cytochrome c-cyanide redox couple was determined for the first time by cyclic voltammetry. Its E 0 ¢ was -240 mV versus SHE, equivalent to -23.2 kJ/mol. The entropy of reaction for the reduction of the cyanide complex was also determined. From a thermodynamic cycle that included this new value for the cyt c cyanide complex E 0 ¢, the binding constant of cyanide to the reduced protein was estimated to be 4.7 · 10 -3 LM -1 or 13.4 kJ/ mol (3.2 kcal/mol), which is 48.1 kJ/mol (11.5 kcal/mol) less favorable than the binding of cyanide to ferricytochrome c. For coordination of cyanide to ferrocytochrome c, the entropy change was earlier experimentally evaluated as 92.4 Jmol -1 K -1 (22.1 e.u.) at 25 K, and the enthalpy change for the same net reaction was calculated to be 41.0 kJ/mol (9.8 kcal/mol). By taking these results into account, it was discovered that the major obstacle to cyanide coordination to ferrocytochrome c is enthalpic, due to the greater compactness of the reduced molecule or, alternatively, to a lower rate of conformational fluctuation caused by solvation, electrostatic, and structural factors. The biophysical consequences of the large difference in the stabilities of the closed crevice structures are discussed.

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Oxidation State-Induced Change of Iron Ligand in the Phenylalanine-82 to Histidine Mutant of Yeast Iso-1-cytochrome c

Cited by 18 publications

References 10 publications

Circular dichroism and resonance Raman comparative studies of wild type cytochrome c and F82H mutant

Circular dichroism and resonance Raman comparative studies of wild type cytochrome c and F82H mutant

Heme Ligation and Conformational Plasticity in the Isolatedc Domain of Cytochrome cd 1 Nitrite Reductase

The redox couple of the cytochrome c cyanide complex: The contribution of heme iron ligation to the structural stability, chemical reactivity, and physiological behavior of horse cytochrome c

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