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Mireille Bruschi - One of the best experts on this subject based on the ideXlab platform.
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Interaction and electron transfer between the high molecular weight Cytochrome and Cytochrome c3 from Desulfovibrio vulgaris Hildenborough: kinetic, microcalorimetric, EPR and electrochemical studies.
Biochimica et biophysica acta, 2005Co-Authors: Marianne Guiral, Mireille Bruschi, Pierre Bianco, Bruno Guigliarelli, Wolfgang Nitschke, Gisèle Leroy, Philippe Gallice, Marie-thérèse Giudici-orticoniAbstract:The complex formation between the tetraheme Cytochrome c3 and hexadecaheme high molecular weight Cytochrome c (Hmc), the structure of which has recently been resolved, has been characterized by cross-linking experiments, EPR, electrochemistry and kinetic analysis, and some key parameters of the interaction were determined. The analysis of electron transfer between [Fe] hydrogenase, Cytochrome c3 and Hmc demonstrates a redox-shuttling role of Cytochrome c3 in the pathway from hydrogenase to Hmc, and shows an effect of redox state on the interaction between the two Cytochromes. The role of polyheme Cytochromes in electron transfer from periplasmic hydrogenase to membrane redox proteins is assessed. A model with Cytochrome c3 as an intermediate between hydrogenase and various polyheme Cytochromes is proposed and its physiological consequences are discussed.
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conformational properties of multihemic Cytochromes c from desulfuromonas acetoxidans
Thermochimica Acta, 2003Co-Authors: M T Giudiciorticoni, V M Lobachov, I I Protasevich, D Lexa, A. A. Makarov, Mireille BruschiAbstract:Abstract In the classification of c-type Cytochromes, the class III includes multihemic Cytochromes c with low redox potential constituting the Cytochrome c3 superfamily. Most of the Cytochromes described have been isolated from sulfate or sulfur reducing bacteria. We report here the comparison between two multihemic Cytochromes, the newly characterized 50 kDa Cytochrome from Desulfuromonas acetoxidans and the Cytochrome c7 from the same strain in order to contribute to understanding the relationships between members of this superfamily. The thermostability of these Cytochromes was studied by circular dichroism (CD) and differential scanning calorimetry (DSC). The influence of the temperature on the redox potential was also investigated. The data clearly indicate the presence of two domains in 50 kDa Cytochrome and a drastic loss of stability of Cytochrome c7 in comparison to Cytochrome c3. The results are discussed in the light of the structural properties of the Cytochrome c3 superfamily and two sub-groups in this family are proposed.
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resonance raman study of multihemic c type Cytochromes from desulfuromonas acetoxidans
FEBS Journal, 2000Co-Authors: Genevia Ve Chottard, Irina Kazanskaya, Mireille BruschiAbstract:Two multihemic Cytochromes c from the sulfur reducing bacteria Desulfuromonas acetoxidans have been studied by optical and resonance Raman spectroscopy: Cytochrome c551.5, a trihemic Cytochrome and Cytochrome c Mr 50 000, a recently isolated high molecular mass Cytochrome. The redox and Raman characteristics of Cytochrome c551.5 are compared to those of the tetrahemic Cytochromes c3 from Desulfovibrio. While the redox behavior, followed by spectroelectrochemistry, is similar to that of Cytochrome c3, showing the same conformational change after reduction of the highest potential heme, the Raman data show a contribution from a His− form of the axial ligands and lead to the assignment of a band at 218 cm−1 to the Fe(III)–(His)2 stretching vibration. The Raman data on Cytochrome c Mr 50 000 are in favor of an entirely low spin species with two different sets of axial ligands. A partially reduced state is easily accessible by ascorbate addition.
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Resonance Raman study of multihemic c‐type Cytochromes from Desulfuromonas acetoxidans
FEBS Journal, 2000Co-Authors: Genevia Ve Chottard, Irina Kazanskaya, Mireille BruschiAbstract:Two multihemic Cytochromes c from the sulfur reducing bacteria Desulfuromonas acetoxidans have been studied by optical and resonance Raman spectroscopy: Cytochrome c551.5, a trihemic Cytochrome and Cytochrome c Mr 50 000, a recently isolated high molecular mass Cytochrome. The redox and Raman characteristics of Cytochrome c551.5 are compared to those of the tetrahemic Cytochromes c3 from Desulfovibrio. While the redox behavior, followed by spectroelectrochemistry, is similar to that of Cytochrome c3, showing the same conformational change after reduction of the highest potential heme, the Raman data show a contribution from a His− form of the axial ligands and lead to the assignment of a band at 218 cm−1 to the Fe(III)–(His)2 stretching vibration. The Raman data on Cytochrome c Mr 50 000 are in favor of an entirely low spin species with two different sets of axial ligands. A partially reduced state is easily accessible by ascorbate addition.
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A sequential electron transfer from hydrogenases to Cytochromes in sulfate-reducing bacteria
Biochimica et Biophysica Acta, 2000Co-Authors: Corinne Aubert, Myriam Brugna, Mireille Bruschi, Alain Dolla, Marie-thérèse Giudici-orticoniAbstract:Abstract A central step in the energy metabolism of sulfate-reducing bacteria is the oxidation of molecular hydrogen, catalyzed by a periplasmic hydrogenase. The resulting electrons are then transferred to various electron transport chains and used for cytoplasmic sulfate reduction. The complex formation between [NiFeSe] hydrogenase and the soluble periplasmic polyheme Cytochromes from Desulfomicrobium norvegicum was characterized by cross-linking experiments, BIAcore and kinetics analysis. Analysis of electron transfer between [NiFeSe] hydrogenase and octaheme Cytochrome c3 (Mr 26 000) pointed out that this Cytochrome is reduced faster in the presence of catalytic amounts of tetraheme Cytochrome c3 (Mr 13 000) isolated from the same organism. The activation of the hydrogenase-dependent reduction of polyheme Cytochromes by Cytochrome c3 (Mr 13 000), which is now described in both Desulfovibrio and Desulfomicrobium, is proposed as a general mechanism. During this process, Cytochrome c3 (Mr 13 000) would act as an electron shuttle in between hydrogenase and the polyheme Cytochromes and its conductivity appears to be an important factor.
Ines A C Pereira - One of the best experts on this subject based on the ideXlab platform.
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Resonance Raman fingerprinting of multiheme Cytochromes from the Cytochrome c _3 family
JBIC Journal of Biological Inorganic Chemistry, 2006Co-Authors: Roberto E. Di Paolo, Patrícia M. Pereira, Ines A C Pereira, Inês Gomes, Filipa M A Valente, Ricardo FrancoAbstract:Resonance Raman (RR) spectroscopy was used to investigate conformational characteristics of the hemes of several ferriCytochromes of the Cytochrome c _3 family, electron transfer proteins isolated from the periplasm and membranes of sulfate-reducing bacteria. Our analysis concentrated on the low-frequency region of the RR spectra, a fingerprint region that includes vibrations for heme-protein C–S bonds [ ν (C_aS)]. It has been proposed that these bonds are directly involved in the electron transfer process. The three groups of tetraheme Cytochrome c _3 analyzed, namely Type I Cytochrome c _3 (TpI c _3s), Type II Cytochrome c _3 (TpII c _3s) and Desulfomicrobium Cytochromes c _3, display different frequency separations for the two ν (C_aS) lines that are similar among members of each group. These spectral differences correlate with differences in protein structure observed among the three groups of Cytochromes c _3. Two larger Cytochromes of the Cytochrome c _3 family display RR spectral characteristics for the ν (C_aS) lines that are closer to TpII c _3 than to TpI c _3. Two other multiheme Cytochromes from Desulfovibrio that do not belong to the Cytochrome c _3 family display ν (C_aS) lines with reverse relative areas in comparison with the latter family. This RR study shows that the small differences in protein structure observed among these Cytochrome c _3 correlate to differences on the heme–protein bonds, which are likely to have an impact upon the protein function, making RR spectroscopy a sensitive and useful tool for characterizing these Cytochromes.
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Resonance Raman fingerprinting of multiheme Cytochromes from the Cytochrome c3 family
Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry, 2005Co-Authors: Roberto E. Di Paolo, Patrícia M. Pereira, Ines A C Pereira, Inês Gomes, Filipa M A Valente, Ricardo FrancoAbstract:Resonance Raman (RR) spectroscopy was used to investigate conformational characteristics of the hemes of several ferriCytochromes of the Cytochrome c3 family, electron transfer proteins isolated from the periplasm and membranes of sulfate-reducing bacteria. Our analysis concentrated on the low-frequency region of the RR spectra, a fingerprint region that includes vibrations for heme-protein C–S bonds [ν(CaS)]. It has been proposed that these bonds are directly involved in the electron transfer process. The three groups of tetraheme Cytochrome c3 analyzed, namely Type I Cytochrome c3 (TpIc3s), Type II Cytochrome c3 (TpIIc3s) and Desulfomicrobium Cytochromes c3, display different frequency separations for the two ν(CaS) lines that are similar among members of each group. These spectral differences correlate with differences in protein structure observed among the three groups of Cytochromes c3. Two larger Cytochromes of the Cytochrome c3 family display RR spectral characteristics for the ν(CaS) lines that are closer to TpIIc3 than to TpIc3. Two other multiheme Cytochromes from Desulfovibrio that do not belong to the Cytochrome c3 family display ν(CaS) lines with reverse relative areas in comparison with the latter family. This RR study shows that the small differences in protein structure observed among these Cytochrome c3 correlate to differences on the heme–protein bonds, which are likely to have an impact upon the protein function, making RR spectroscopy a sensitive and useful tool for characterizing these Cytochromes.
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sulfate respiration in desulfovibrio vulgaris hildenborough structure of the 16 heme Cytochrome c hmca at 2 5 a resolution and a view of its role in transmembrane electron transfer
Journal of Biological Chemistry, 2002Co-Authors: Pedro M Matias, Ines A C Pereira, Antonio V Xavier, Jean Legall, Filipa M A Valente, Ana V Coelho, Diana Placido, Maria Armenia CarrondoAbstract:Abstract The crystal structure of the high molecular mass Cytochrome c HmcA from Desulfovibrio vulgarisHildenborough is described. HmcA contains the unprecedented number of sixteen hemes c attached to a single polypeptide chain, is associated with a membrane-bound redox complex, and is involved in electron transfer from the periplasmic oxidation of hydrogen to the cytoplasmic reduction of sulfate. The structure of HmcA is organized into four tetraheme Cytochrome c 3-like domains, of which the first is incomplete and contains only three hemes, and the final two show great similarity to the nine-heme Cytochromec from Desulfovibrio desulfuricans. An isoleucine residue fills the vacant coordination space above the iron atom in the five-coordinated high-spin Heme 15. The characteristics of each of the tetraheme domains of HmcA, as well as its surface charge distribution, indicate this Cytochrome has several similarities with the nine-heme Cytochrome c and the Type II Cytochromec 3 molecules, in agreement with their similar genetic organization and mode of reactivity and further support an analogous physiological function for the three Cytochromes. Based on the present structure, the possible electron transfer sites between HmcA and its redox partners (namely Type I Cytochromec 3 and other proteins of the Hmc complex), as well as its physiological role, are discussed.
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a membrane bound Cytochrome c3 a type ii Cytochrome c3 from desulfovibrio vulgaris hildenborough
ChemBioChem, 2001Co-Authors: Filipa M A Valente, Miguel Teixeira, Ligia M Saraiva, Antonio V Xavier, Jean Legall, Ines A C PereiraAbstract:A new tetraheme Cytochrome c3 was isolated from the membranes of Desulfovibrio vulgaris Hildenborough (DvH). This Cytochrome has a molecular mass of 13.4 kDa and a pI of 5.5 and contains four heme c groups with apparent reduction potentials of -170 mV, -235 mV, -260 mV and -325 mV at pH 7.6. The complete sequence of the new Cytochrome, retrieved from the preliminary data of the DvH genome, shows that this Cytochrome is homologous to the "acidic" Cytochrome c3 from Desulfovibrio africanus (Da). A model for the structure of the DvH Cytochrome was built based on the structure of the Da Cytochrome. Both Cytochromes share structural features that distinguish them from other Cytochrome c3 proteins, such as a solvent-exposed heme 1 surrounded by an acidic surface area, and a heme 4 which lacks most of the surface lysine patch proposed to be the site of hydrogenase interaction in other Cytochrome c3 proteins. Furthermore, in contrast to previously discovered Cytochrome c3 proteins, the genes coding for these two Cytochromes are adjacent to genes coding for two membrane-associated FeS proteins, which indicates that they may be part of membrane-bound oxidoreductase complexes. Altogether these observations suggest that the DvH and Da Cytochromes are a new type of Cytochrome c3 proteins (Type II: TpII-c3) with different redox partners and physiological function than the other Cytochrome c3 proteins (Type I: TpI-c3). The DvH TpII-c3 is reduced at considerable rates by the two membrane-bound [NiFe] and [NiFeSe] hydrogenases, but catalytic amounts of TpI-c3 increase these rates two- and fourfold, respectively. With the periplasmic [Fe] hydrogenase TpII-c3 is reduced much slower than TpI-c3, and no catalytic effect of TpI-c3 is observed.
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multiheme Cytochromes from the sulfur reducing bacterium desulfuromonas acetoxidans
FEBS Journal, 1997Co-Authors: Ines A C Pereira, Antonio V Xavier, Jean Legall, Isabel Pacheco, Miguel TeixeiraAbstract:Two new multiheme Cytochromes were isolated from the anaerobic sulfur reducing bacterium Desulfuromonas acetoxidans. They have monomeric molecular masses of 50 and 65 kDa and contain six and eight hemes, respectively. Visible and EPR spectroscopies, in the as-isolated (oxidised) Cytochromes, show the presence of only low-spin hemes in the 50-kDa Cytochrome, and of high-spin and low-spin hemes in the 65-kDa Cytochrome. The EPR spectra of the native 65-kDa Cytochrome indicate multiple heme–heme interactions, including integer-spin systems as judged by parallel-mode EPR. The 50-kDa Cytochrome has a complex redox pattern, as shown by EPR redox titrations, and contains one heme with unusual characteristics. Both Cytochromes cover an extremely wide range of reduction potentials, which go from +100 mV to -375 mV for the 50-kDa Cytochrome, and +185 mV to -235 mV for the 65-kDa Cytochrome. The two Cytochromes were tested for hydroxylamine oxidoreductase activity and polysulfide reductase activity, but neither displayed any activity. In contrast, it was found for the first time that the previously characterised Cytochrome c551.5, from the same bacterium is very active in the reduction of polysulfide, which suggests that it acts as a terminal reductase in D. acetoxidans.
T E Meyer - One of the best experts on this subject based on the ideXlab platform.
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identification of 42 possible Cytochrome c genes in the shewanella oneidensis genome and characterization of six soluble Cytochromes
Omics A Journal of Integrative Biology, 2004Co-Authors: T E Meyer, A I Tsapin, Isabel Vandenberghe, Kenneth H Nealson, Michael A Cusanovich, Lina De Smet, Dmitrij Frishman, Jozef Van BeeumenAbstract:Through pattern matching of the Cytochrome c heme-binding site (CXXCH) against the genome sequence of Shewanella oneidensis MR-1, we identified 42 possible Cytochrome c genes (27 of which should be soluble) out of a total of 4758. However, we found only six soluble Cytochromes c in extracts of S. oneidensis grown under several different conditions: (1) a small tetraheme Cytochrome c, (2) a tetraheme flavoCytochrome c-fumarate reductase, (3) a diheme Cytochrome c4, (4) a monoheme Cytochrome c5, (5) a monoheme Cytochrome c′, and (6) a diheme bacterial Cytochrome c peroxidase. These Cytochromes were identified either through N-terminal or complete amino acid sequence determination combined with mass spectroscopy. All six Cytochromes were about 10-fold more abundant when cells were grown at low than at high aeration, whereas the flavoCytochrome c-fumarate reductase was specifically induced by anaerobic growth on fumarate. When adjusted for the different heme content, the monoheme Cytochrome c5 is as abundant ...
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identification of a small tetraheme Cytochrome c and a flavoCytochrome c as two of the principal soluble Cytochromes c in shewanella oneidensis strain mr1
Applied and Environmental Microbiology, 2001Co-Authors: A I Tsapin, Isabel Vandenberghe, Kenneth H Nealson, J H Scott, T E Meyer, Michael A Cusanovich, E Harada, T Kaizu, Hideo Akutsu, David LeysAbstract:Two abundant, low-redox-potential Cytochromes c were purified from the facultative anaerobe Shewanella oneidensis strain MR1 grown anaerobically with fumarate. The small Cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. The small Cytochrome c contains 91 residues and four heme binding sites. It is most similar to the Cytochromes c from Shewanella frigidimarina (formerly Shewanella putrefaciens) NCIMB400 and the unclassified bacterial strain H1R (64 and 55% identity, respectively). The amount of the small tetraheme Cytochrome is regulated by anaerobiosis, but not by fumarate. The larger of the two low-potential Cytochromes contains tetraheme and flavin domains and is regulated by anaerobiosis and by fumarate and thus most nearly corresponds to the flavoCytochrome c-fumarate reductase previously characterized from S. frigidimarina to which it is 59% identical. However, the genetic context of the Cytochrome genes is not the same for the two Shewanella species, and they are not located in multicistronic operons. The small Cytochrome c and the Cytochrome domain of the flavoCytochrome c are also homologous, showing 34% identity. Structural comparison shows that the Shewanella tetraheme Cytochromes are not related to the Desulfovibrio Cytochromes c3 but define a new folding motif for small multiheme Cytochromes c.
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Electron transfer proteins of the purple phototrophic bacterium, Rhodopseudomonas rutila.
Archives of Biochemistry and Biophysics, 1991Co-Authors: T.e. Meyer, R. G. Bartsch, U. Fischer, G. Van Driessche, J. Van Beeumen, J. Fitch, T E Meyer, M. A. CusanovichAbstract:Abstract The soluble electron transfer protein content of Rhodopseudomonas rutila was found to consist of two basic Cytochromes and a (4Fe-4S) ferredoxin. Cytochrome c ′ was easily identified by its characteristic high spin absorption spectra. The native molecular weight is 29,000 and the subunit is 14,000. Cytochrome c -550 has low spin absorption spectra and a high redox potential (376 mV) typical of Cytochromes c 2 . The molecular weight is about 14,000. The ferredoxin is apparently a dimer (43,000) of approximately 18,000 Da subunits. There are 1.3 to 1.5 iron-sulfur clusters per monomer of 18-to 21-kDa protein. The N-terminal amino acid sequence is like the (7Fe-8S) ferredoxins of Rhodobacter capsulatus and Azotobacter vinelandii . Remarkably, there are only 2 or 3 out of 25 amino acid substitutions. Difference absorption spectra of Rps. rutila membranes indicate that there is no tetraheme reaction center Cytochrome c , such as is characteristic of Rps. viridis . However, there are a high potential Cytochrome c and a low potential Cytochrome b in the membrane, which are suggestive of a Cytochrome bc 1 complex. Rps. rutila is most similar to Rps. palustris in microbiological properties, yet it does not have the Cytochromes c -556, c -554, and c -551 in addition to c 2 and c ′, which are characteristic of Rps. palustris . Furthermore, the Rps. rutila Cytochrome c ′ is dimeric, whereas the same protein from Rps. palustris is the only one known to be monomeric. The Cytochrome pattern is more like that of Rhodospirillum rubrum and Rb. capsulatus , which are apparently only able to make Cytochromes c 2 and c ′.
Michael A Cusanovich - One of the best experts on this subject based on the ideXlab platform.
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identification of 42 possible Cytochrome c genes in the shewanella oneidensis genome and characterization of six soluble Cytochromes
Omics A Journal of Integrative Biology, 2004Co-Authors: T E Meyer, A I Tsapin, Isabel Vandenberghe, Kenneth H Nealson, Michael A Cusanovich, Lina De Smet, Dmitrij Frishman, Jozef Van BeeumenAbstract:Through pattern matching of the Cytochrome c heme-binding site (CXXCH) against the genome sequence of Shewanella oneidensis MR-1, we identified 42 possible Cytochrome c genes (27 of which should be soluble) out of a total of 4758. However, we found only six soluble Cytochromes c in extracts of S. oneidensis grown under several different conditions: (1) a small tetraheme Cytochrome c, (2) a tetraheme flavoCytochrome c-fumarate reductase, (3) a diheme Cytochrome c4, (4) a monoheme Cytochrome c5, (5) a monoheme Cytochrome c′, and (6) a diheme bacterial Cytochrome c peroxidase. These Cytochromes were identified either through N-terminal or complete amino acid sequence determination combined with mass spectroscopy. All six Cytochromes were about 10-fold more abundant when cells were grown at low than at high aeration, whereas the flavoCytochrome c-fumarate reductase was specifically induced by anaerobic growth on fumarate. When adjusted for the different heme content, the monoheme Cytochrome c5 is as abundant ...
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Discovery and characterization of electron transfer proteins in the photosynthetic bacteria.
Photosynthesis research, 2003Co-Authors: Terrance E. Meyer, Michael A CusanovichAbstract:Research on photosynthetic electron transfer closely parallels that of other electron transfer pathways and in many cases they overlap. Thus, the first bacterial Cytochrome to be characterized, called Cytochrome c (2), is commonly found in non-sulfur purple photosynthetic bacteria and is a close homolog of mitochondrial Cytochrome c. The Cytochrome bc (1) complex is an integral part of photosynthetic electron transfer yet, like Cytochrome c (2), was first recognized as a respiratory component. Cytochromes c (2) mediate electron transfer between the Cytochrome bc (1) complex and photosynthetic reaction centers and Cytochrome a-type oxidases. Not all photosynthetic bacteria contain Cytochrome c (2); instead it is thought that HiPIP, auracyanin, Halorhodospira Cytochrome c551, Chlorobium Cytochrome c555, and Cytochrome c (8) may function in a similar manner as photosynthetic electron carriers between the Cytochrome bc (1) complex and reaction centers. More often than not, the soluble or periplasmic mediators do not interact directly with the reaction center bacteriochlorophyll, but require the presence of membrane-bound intermediates: a tetraheme Cytochrome c in purple bacteria and a monoheme Cytochrome c in green bacteria. Cyclic electron transfer in photosynthesis requires that the redox potential of the system be delicately poised for optimum efficiency. In fact, lack of redox poise may be one of the defects in the aerobic phototrophic bacteria. Thus, large concentrations of Cytochromes c (2) and c' may additionally poise the redox potential of the cyclic photosystem of purple bacteria. Other Cytochromes, such as flavoCytochrome c (FCSD or SoxEF) and Cytochrome c551 (SoxA), may feed electrons from sulfide, sulfur, and thiosulfate into the photosynthetic pathways via the same soluble carriers as are part of the cyclic system.
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identification of a small tetraheme Cytochrome c and a flavoCytochrome c as two of the principal soluble Cytochromes c in shewanella oneidensis strain mr1
Applied and Environmental Microbiology, 2001Co-Authors: A I Tsapin, Isabel Vandenberghe, Kenneth H Nealson, J H Scott, T E Meyer, Michael A Cusanovich, E Harada, T Kaizu, Hideo Akutsu, David LeysAbstract:Two abundant, low-redox-potential Cytochromes c were purified from the facultative anaerobe Shewanella oneidensis strain MR1 grown anaerobically with fumarate. The small Cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. The small Cytochrome c contains 91 residues and four heme binding sites. It is most similar to the Cytochromes c from Shewanella frigidimarina (formerly Shewanella putrefaciens) NCIMB400 and the unclassified bacterial strain H1R (64 and 55% identity, respectively). The amount of the small tetraheme Cytochrome is regulated by anaerobiosis, but not by fumarate. The larger of the two low-potential Cytochromes contains tetraheme and flavin domains and is regulated by anaerobiosis and by fumarate and thus most nearly corresponds to the flavoCytochrome c-fumarate reductase previously characterized from S. frigidimarina to which it is 59% identical. However, the genetic context of the Cytochrome genes is not the same for the two Shewanella species, and they are not located in multicistronic operons. The small Cytochrome c and the Cytochrome domain of the flavoCytochrome c are also homologous, showing 34% identity. Structural comparison shows that the Shewanella tetraheme Cytochromes are not related to the Desulfovibrio Cytochromes c3 but define a new folding motif for small multiheme Cytochromes c.
Françoise Guerlesquin - One of the best experts on this subject based on the ideXlab platform.
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Letter to the Editor: Sequential NMR assignment of the ferri-Cytochrome c3 from Desulfovibrio vulgaris Hildenborough
Journal of Biomolecular NMR, 2002Co-Authors: Latifa Elantak, Alain Dolla, Olivier Bornet, Xavier Morelli, Françoise GuerlesquinAbstract:Cytochromes c3 are low redox potential Cytochromes involved in anaerobic metabolism. These periplasmic proteins contain four bi-histidinyl coordinated hemes. Multiheme Cytochromes have been found in sulfate reducing bacteria of the genus Desulfovibrio. Preliminary analysis of Desulfovibrio vulgaris Hildenborough genome pointed out the existence of several putative genes encoding tetraheme Cytochromes (http://www.tigr.org). Analysis of their genomic context showed that some of them are isolated (i.e., the gene encoding the well known soluble Cytochrome c3 (Mr 13,000)) while others are part of multienzymatic complexes (i.e., the tetraheme Cytochrome subunit in formate dehydrogenase (Sebban et al., 1995)). The large diversity of the tetraheme Cytochromes in this organism must be correlated with the great specificity of these molecules for their oxidoreduction partners. We have recently reported a new approach to study electron transfer complexes combining NMR spectroscopy and theoretical calculations. 1H-15N HSQC are performed on an 15N-labelled redox partner, and we use the chemical shift variations induced upon complex formation to map the interacting site and to filter the ab initio models obtained by Bigger (Morelli et al., 2000). 1H-15N HSQC assignment is thus the first step of the functional study of Cytochromes c3. We have initiated our studies with the soluble Cytochrome c3 (Mr 13,000). The gene of this protein was cloned and sequenced (Voordouw et al., 1985) and the structure of this tetraheme Cytochrome was solved by x-ray (Matias et al., 1993).
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crystal structure of a dimeric octaheme Cytochrome c3 mr 26000 from desulfovibrio desulfuricans norway
Structure, 1996Co-Authors: Mirjam Czjzek, Mireille Bruschi, Françoise Guerlesquin, R. HaserAbstract:Abstract Background: The octaheme Cytochrome c 3 (M r 26000; cc 3 ) from Desulfovibrio desulfuricans Norway is a dimeric Cytochrome made up of two identical subunits, each containing four heme groups. It is involved in the redox transfer chain of sulfate-reducing bacteria, which links the periplasmic oxidation of hydrogen to the cytoplasmic reduction of sulfate. The amino-acid sequence of cc 3 shows similarities to that of the tetraheme Cytochrome c 3 (M r 13000; c 3 ) from the same bacteria. Structural analysis of cc 3 forms a basis for understanding the precise roles of the multiheme-containing redox proteins and the reason for the presence of several different multiheme Cytochromes in one bacterial strain. Results The crystal structure of Cytochrome cc 3 has been determined at 2.16 a resolution. The subunits display the c 3 structural fold with significant amino-acid substitutions, relative to the tetraheme Cytochromes c 3 , in the regions of the dimer interface. The identical subunits are related by a crystallographic twofold axis, with one heme of each subunit in close contact. The overall structure and the environments of the different heme groups are compared with those of the tetraheme Cytochromes c 3 . Conclusion A common scheme for interactions between these types of Cytochrome and their redox partners involves the interaction of a heme crevice, surrounded by positively charged lysine residues, with acidic residues surrounding the redox partner's functional group. Despite the relatively acidic character of Cytochrome cc 3 , the crevice of one heme is surrounded by a high number of positively charged residues, in the same manner as has been reported for Cytochromes c 3 . The environment of this heme is formed by four flexible surface loops which are variable in length and orientation in the different c 3 -type Cytochromes although the overall structural folds are very similar. It has been proposed that this region, adapted in topology and charge, is the interaction site for physiological partners and is also most likely to be the interaction site in the dimeric Cytochrome cc 3 .
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Crystal structure of a dimeric octaheme Cytochrome c3 (M(r) 26,000) from Desulfovibrio desulfuricans Norway.
Structure, 1996Co-Authors: Mirjam Czjzek, Françoise Guerlesquin, M. Bruschi, R. HaserAbstract:BACKGROUND: The octaheme Cytochrome C3 (M(r) 26,000; cc3) from Desulfovibrio desulfuricans Norway is a dimeric Cytochrome made up of two identical subunits, each containing four heme groups. It is involved in the redox transfer chain of sulfate-reducing bacteria, which links the periplasmic oxidation of hydrogen to the cytoplasmic reduction of sulfate. The amino-acid sequence of cc3 shows similarities to that of the tetraheme Cytochrome c3 (M(r) 13,000; c3) from the same bacteria. Structural analysis of cc3 forms a basis for understanding the precise roles of the multiheme-containing redox proteins and the reason for the presence of several different multiheme Cytochromes in one bacterial strain. RESULTS: The crystal structure of Cytochrome cc3 has been determined at 2.16 A resolution. The subunits display the c3 structural fold with significant amino-acid substitutions, relative to the tetraheme Cytochromes c3, in the regions of the dimer interface. The identical subunits are related by a crystallographic twofold axis, with one heme of each subunit in close contact. The overall structure and the environments of the different heme groups are compared with those of the tetraheme Cytochromes c3. CONCLUSIONS: A common scheme for interactions between these types of Cytochrome and their redox partners involves the interaction of a heme crevice, surrounded by positively charged lysine residues, with acidic residues surrounding the redox partner's functional group. Despite the relatively acidic character of Cytochrome cc3, the crevice of one heme is surrounded by a high number of positively charged residues, in the same manner as has been reported for Cytochromes c3. The environment of this heme is formed by four flexible surface loops which are variable in length and orientation in the different c3-type Cytochromes although the overall structural folds are very similar. It has been proposed that this region, adapted in topology and charge, is the interaction site for physiological partners and is also most likely to be the interaction site in the dimeric Cytochrome cc3.BACKGROUND: The octaheme Cytochrome C3 (M(r) 26,000; cc3) from Desulfovibrio desulfuricans Norway is a dimeric Cytochrome made up of two identical subunits, each containing four heme groups. It is involved in the redox transfer chain of sulfate-reducing bacteria, which links the periplasmic oxidation of hydrogen to the cytoplasmic reduction of sulfate. The amino-acid sequence of cc3 shows similarities to that of the tetraheme Cytochrome c3 (M(r) 13,000; c3) from the same bacteria. Structural analysis of cc3 forms a basis for understanding the precise roles of the multiheme-containing redox proteins and the reason for the presence of several different multiheme Cytochromes in one bacterial strain. RESULTS: The crystal structure of Cytochrome cc3 has been determined at 2.16 A resolution. The subunits display the c3 structural fold with significant amino-acid substitutions, relative to the tetraheme Cytochromes c3, in the regions of the dimer interface. The identical subunits are related by a crystallographic twofold axis, with one heme of each subunit in close contact. The overall structure and the environments of the different heme groups are compared with those of the tetraheme Cytochromes c3. CONCLUSIONS: A common scheme for interactions between these types of Cytochrome and their redox partners involves the interaction of a heme crevice, surrounded by positively charged lysine residues, with acidic residues surrounding the redox partner's functional group. Despite the relatively acidic character of Cytochrome cc3, the crevice of one heme is surrounded by a high number of positively charged residues, in the same manner as has been reported for Cytochromes c3. The environment of this heme is formed by four flexible surface loops which are variable in length and orientation in the different c3-type Cytochromes although the overall structural folds are very similar. It has been proposed that this region, adapted in topology and charge, is the interaction site for physiological partners and is also most likely to be the interaction site in the dimeric Cytochrome cc3.
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amino acid sequence of the Cytochrome c3 mr 26 000 from desulfovibrio desulfuricans norway and a comparison with those of the other polyhemic Cytochromes from desulfovibrio
Biochimica et Biophysica Acta, 1994Co-Authors: Mireille Bruschi, Françoise Guerlesquin, Gisèle Leroy, J BonicelAbstract:Abstract The amino-acid sequence of an octaheme Cytochrome c 3 isolated from Desulfovibrio desulfuricans Norway is presented. The protein molecule ( M r 26 000) comprises two identical subunits of 111 amino acids with the characteristics typical of tetrahemic Cytochrome c 3 class. Comparisons between the amino-acid sequences and physiological properties of Cytochrome c 3 ( M r 26 000) and Cytochromes c 3 ( M r 13 000) isolated from various species of Desulfovibrio showed the existence of considerable differences. In order to distinguish between the various subclasses in the Cytochrome c 3 superfamily, the amino-acid sequence of Cytochrome c 3 ( M r 26000 ) was compared with six known Cytochrome c 3 ( M r 13000 ) sequences as well as with the sequence of the four c 3 -like domains of a high molecular weight Cytochrome c (Hmc) containing 16 hemes per molecule of 65 500 Da, isolated from Desulfovibrio vulgaris Hildenborough. The evolution and phylogenetic relationships of these various polyhemic Cytochromes are discussed.
