EPR redox study of cytochrome c3 from Desulfovibrio vulgaris Miyazaki

Gayda, Jean‐Pierre; Yagi, Takeshi; Benosman, Haféda; Bertrand, Patrick

doi:10.1016/0014-5793(87)81242-5

Cited by 34 publications

(20 citation statements)

References 19 publications

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“…Modifications of the method have been introduced to take into account the existence in the oxidized state of two distinct conformational states for heme 4 and their interconversion which occurs when heme 1 is reduced. As expected from our previous work [6], we found that, as in DdNc3, the redox interactions are moderate, with absolute values less than 25 mV. Our results disagree with an earlier interpretation of electrochemical measurements on DvMc3 in which two hemes were thought to be equivalent and independent of the other two hemes [9].…”

contrasting

confidence: 76%

“…Spectral modifications of heme 4 are also observed during the redox titration of DvMc3 [6]. However the situation is more complicated in the present case.…”

Section: Measurements Of the Redox Parametersmentioning

confidence: 58%

“…This region is particularly sensitive to the conversion process so that a more precise fit would certainly require a description of this conversion by a model involving more than one parameter. In our previous work on the redox properties of DvMc3 [6], the downfield shift of 75 G of the high-field peak at g = 1.59 which accompanies the reduction of heme 1, was attributed to a variation of the g values of heme 4 induced by structural modifications. It is possible to show that in fact this shift is compatible with our new interpretation based on an interconversion between the two conformations 4a and 4 b of heme4: we performed simulations of the g , region of the spectra with a method similar to that used in the lowfield region.…”

Section: Measurement Of the Redox Parametersmentioning

confidence: 94%

“…The sample preparation and the experimental conditions relative to the EPR redox titration are described elsewhere [6]. We recall here that the redox potentials were adjusted at 21 "C by using dithionite as the reductant in the presence of redox mediators.…”

Section: Methods Experimenta1 Proceduresmentioning

confidence: 99%

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EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

Benosman

Asso

Bertrand

et al. 1989

European Journal of Biochemistry

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We present a new examination of the EPR redox titration data for the tetraheme cytochrome c3 from Desulfovihrio vulgaris Miyazaki. Our analysis includes the contribution of the interaction potentials between the four redox sites and is based on the model previously developed for the study of cytochrome c3 from Desulfovihrio desulfuricans Norway. We observed, as for D. desulfuricans Norway cytochrome c3, that the conformation of the heme with the lowest redox potential, heme 4, is sensitive to the redox state of the heme with the highest potential, heme 1. However in D. vulgaris Miyazaki cytochrome c3 spectral simulations show that heme 4 is present in two conformational states which interconvert partially when heme 1 is reduced. The sets of redox parameters which satisfy the fitting procedure of the titration curves are in the following domain: -250 mV I ef I -220mV, -325mV I e2 I -320mV, -335mV 5 e3 5 -330mV, -360mV I e4 I -355mV, -5mV I I I 2 5 20mV, -10mV I I I 3 I 5mV, -15mV I I 2 3 5 -5mV, -15mV I I 2 4 I -10mV, -25mV I 134 I -15mV. As in D. desulfuricans Norway cytochrome c3 the interactions are moderate. Simple electrostatic considerations suggest that these moderate values could be related to the large accessibility of the hemes to the solvent. Our work does not confirm the existence of a cooperative interaction between heme 2 and heme 3 which has been proposed on the basis of electrochemical measurements.In biological electron carriers containing several redox sites, cooperative and anticooperative redox interactions could play a significant role in the activity. The tetraheme cytochrome c3, where the four redox sites are closely packed, appears as a good model for a study of these interactions. The three-dimensional structure is known for two different species, the cytochrome c3 from Desulfovihrio desulfuricans Norway (DdNc3) [l] and the cytochrome c3 from Desulfovihrio vulgaris Miyazaki (DvMc3) [2]. Precise calculations of electrostatic energies should then be possible in order to determine the main factors involved in the redox properties such as the accessibility to the solvent and the influence of the dipoles, permanent or induced, the ionized groups and the conformational variations accompanying the change of the redox state [3,4]. The present work is a part of our program concerning the experimental investigation of the redox properties of these systems [5 -71.The first data on redox interactions were obtained on cytochrome c3 from Desulfovihrio gigas (Dgc,) with an original method based on redox titrations followed by NMR spectroscopy [XI. They indicated the existence of cooperative redox interactions larger than + 40 mV and a pH dependence of the redox parameters. We have developed recently a different approach based on EPR redox titrations [7]. Application of our method to DdNc3 has shown that the interactions between hemes 2, 3 and 4 (numbered in order of decreasing redox potentials) are moderate, with absolute values smaller than 15 mV, and a spectrophotometric redox titration indicated no ...

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contrasting

confidence: 76%

“…Spectral modifications of heme 4 are also observed during the redox titration of DvMc3 [6]. However the situation is more complicated in the present case.…”

Section: Measurements Of the Redox Parametersmentioning

confidence: 58%

Section: Measurement Of the Redox Parametersmentioning

confidence: 94%

Section: Methods Experimenta1 Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

Benosman

Asso

Bertrand

et al. 1989

European Journal of Biochemistry

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“…The site-specific heme assignments were also.supported by NOE between the methyl groups of these hemes and the side chain ofVaP s. All the results contradicted the.heme assignments for D.v. MF cytochrome c3 made on the basis of electron spin resonance (Gayda et al (1987) FEBS Lett., 217 57-61). Based on these assignments, the interaction of cytochrome c3 with D.v.…”

mentioning

confidence: 99%

1H NMR studies on ferricytochromec 3 fromDesulfovibrio vulgaris Miyazaki F and its interaction with ferredoxin I

et al. 1991

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The 1H NMR signals of the heme methyl, propionate and related chemical groups of cytochrome c3 from Desulfovibrio vulgaris Miyazaki F (D.v. MF) were site-specifically assigned by means of 1D NOE, 2D DQFCOSY and 2D TOCSY spectra. They were consistent with the site-specific assignments of the hemes with the highest and second-lowest redox potentials reported by Fan et al. (Biochemistry, 29 (1990) 2257-2263). The site-specific heme assignments were also supported by NOE between the methyl groups of these hemes and the side chain of Val18. All the results contradicted the heme assignments for D.v. MF cytochrome c3 made on the basis of electron spin resonance (Gayda et al. (1987) FEBS Lett., 217 57-61). Based on these assignments, the interaction of cytochrome c3 with D.v. MF ferredoxin I was investigated by NMR. The major interaction site of cytochrome c3 was identified as the heme with the highest redox potential, which is surrounded by the highest density of positive charges. The stoichiometry and association constant were two cytochrome c3 molecules per monomer of ferredoxin I and 10(8) M-2 (at 53 mM ionic strength and 25 degrees C), respectively.

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Iron Porphyrin Chemistry

Walker¹,

Simonis²

2005

Encyclopedia of Inorganic Chemistry

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This article reviews most aspects of the chemistry of iron porphyrins, from Fe(0) to Fe(V), including occurrence and roles of natural iron porphyrins (hemes) and their synthetic analogs, structures and electron configurations of iron porphyrins of all oxidation and spin states, π electron configuration of the porphyrin ring, synthesis of metal‐free porphyrins and other related macrocycles, insertion of iron into free‐base porphyrins and related macrocycles, the properties, reactions, uses and biological relevance of iron(0), ‐(I), ‐(II) porphyrins (the latter with S = 0, 1, and 2 spin state possibilities), of iron(II) porphyrin π‐cation radicals, of iron(III) porphyrins (with S = 1/2, 3/2, and 5/2 spin state possibilities), of iron(III) porphyrin and corrole π‐cation radicals, of iron(IV) porphyrins (including five‐ and six‐coordinate ferryl (FeO) 2+ , iron(IV) phenyl, carbene and hydrazine complexes, and the bis‐methoxide complex) and a comparison of iron(IV) porphyrins to iron(III) porphyrin π‐cation radicals, of iron(IV) porphyrin π‐cation radicals, and of the possible existence of iron(V) porphyrins. Included in the Fe(II) part are sections on addition of ligands to four‐coordinate iron(II) porphyrins, including equilibrium binding constants, photodissociation of ligands from PFeL 2 complexes, binding of small molecules (O 2 , CO, NO, HNO) to 5‐coordinate iron(II) porphyrins and design of porphyrin ligands that will mimic the active sites of heme proteins such as myoglobin and hemoglobin, the cytochromes P450 and nitric oxide synthases, and the nitrophorins and guanylyl cyclases. Included in the iron(III) part are sections on both 5‐ and 6‐coordinate high‐spin complexes and their similarities and differences, bridged or through‐space magnetically coupled complexes of high‐spin iron(III) porphyrins with other metal complexes as possible models for cytochrome oxidase and the assimilatory sulfite reductases, coupled oxidation of hemes by hydrogen peroxide or its equivalent, and the relationship of this reactivity to the reactions of heme oxygenase, iron(III) porphyrins as reduction catalysts, and photochemistry of iron(III) porphyrins, possible electron configurations of low‐spin iron(III) porphyrins, the phenomenon and possible electronic consequences of ruffling of the porphinato core in iron(III) porphyrins, the preferred orientation of planar axial ligands bound to low‐spin iron(III) porphyrins, NO complexes of iron(III) porphyrins, reduction potentials, equilibrium constants and rates of axial‐ligand addition and exchange, kinetics of axial‐ligand rotation and porphyrin ring inversion, kinetics of reduction and autoreduction of iron(III) porphyrins, electron self‐exchange between low‐spin iron(III) and iron(II) porphyrins, synthetic ferriheme proteins, and synthesis of five‐coordinate low‐spin iron(III) porphyrins having σ‐alkyl or σ‐aryl groups as axial ligands. The iron(IV) and iron(IV) cation radical sections discuss the high‐valent states of cytochromes P450 and related enzymes.

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EPR redox study of cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

Cited by 34 publications

References 19 publications

EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

1H NMR studies on ferricytochromec 3 fromDesulfovibrio vulgaris Miyazaki F and its interaction with ferredoxin I

Iron Porphyrin Chemistry

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EPR redox study of cytochrome c3 from Desulfovibrio vulgaris Miyazaki

Cited by 34 publications

References 19 publications

EPR study of the redox interactions in cytochrome c3 from Desulfovibrio vulgaris Miyazaki

EPR study of the redox interactions in cytochrome c3 from Desulfovibrio vulgaris Miyazaki

1H NMR studies on ferricytochromec 3 fromDesulfovibrio vulgaris Miyazaki F and its interaction with ferredoxin I

Iron Porphyrin Chemistry

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EPR redox study of cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki

EPR study of the redox interactions in cytochrome c₃ from Desulfovibrio vulgaris Miyazaki