Cytochrome <i>c</i>: A Thermodynamic Study of the Relationships among Oxidation State, Ion‐Binding and Structural Parameters

Margalit, Rimona; Schejter, Abel

doi:10.1111/j.1432-1033.1973.tb02633.x

Cited by 209 publications

(79 citation statements)

References 20 publications

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“…o mV for Desulfovibrio cytochromes c-553 (Table 2) (Bertrand et al 1982). However, in eucariotic cytochromes c the heat and entropy of reaction corresponding to the redox couples have been highly conserved during phylogenetic evolution (Margalit & Schejter, 1973;Dickerson & Timkovitch, 1975;Pettigrew, Aviram & Schejter, 1975) and the redox potentials observed for mitochrondrial cytochromes c are all close to 260 mV (Table 2).…”

Section: Correlation Between the Co-ordination Geometry Of The Axial mentioning

confidence: 95%

Amino acid sequence, haem-iron co-ordination geometry and functional properties of mitochondrial and bacterial c-type cytochromes

Senn

Wüthrich

1985

Quart. Rev. Biophys.

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Cytochromes are found in all biological oxidation Systems which involve transport of reducing equivalents through organized chains of membrane bound intermediates, regardless of the ultimate oxidant (Keilin, 1966; Bartsch, 1978; Meyer & Kamen, 1982). Thus, cytochromes are present not only in the aerobic mitochondrial and bac-terial respiratory chain, but are also found in much more diversified procariotic Systems, including all varieties of facultative anaerobes (nitrate and nitrite reducers), obligate anaerobes (sulphate reducers and phototrophic sulphur bacteria), facultative photoheterotrophes (phototrophic non-sulphur purple bacteria), and the photoautotrophic cyanobacteria (blue-green algae). Among the different types of cytochromes occurring in the cell, the soluble c-type cytochromes (‘class I’, Meyer & Kamen, 1982) are the most abundant and best characterized group of proteins (Bartsch, 1978; Meyer & Kamen, 1982; Dickerson & Timkovitch, 1975; Lemberg & Barrett, 1973; Salemme, 1977; Ferguson-Miller, Brautigan & Margoliash, 1979). The amino acid sequences of more than 80 mitochrondrial and close to 40 bacterial cytochromes c are known (Meyer & Kamen, 1982; Dickerson & Timkovitch, 1975; Schwartz & Dayhoff, 1976; Dayhoff & Barker, 1978).

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Section: Correlation Between the Co-ordination Geometry Of The Axial mentioning

confidence: 95%

Amino acid sequence, haem-iron co-ordination geometry and functional properties of mitochondrial and bacterial c-type cytochromes

Senn

Wüthrich

1985

Quart. Rev. Biophys.

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“…An even wider range has been reported for the binding of chloride, with KD values varying from 2 X 10-6 M to 5.9 X 10-2 M for ferricytochrome c (4,6,20,23) and from 1 X 10-2 M to no detectable binding for ferrocytochrome c (4,6,20,23 …”

Section: §)mentioning

confidence: 98%

“…A further complication is that the reported dissociation constants for the binding of phosphate to ferricytochrome c vary from 2.3 X 10-5 M to 5.9 X 10-2 M (4, 6, 16, 23) and to ferrocytochrome c, from 1 X 10-2 M to no detectable interaction (4,6,21,23). An even wider range has been reported for the binding of chloride, with KD values varying from 2 X 10-6 M to 5.9 X 10-2 M for ferricytochrome c (4,6,20,23) and from 1 X 10-2 M to no detectable binding for ferrocytochrome c (4,6,20,23 …”

Section: §)mentioning

confidence: 99%

“…Binding stoichiometries, affinities, and locations have since been examined by a variety of techniques. Among these are direct measurements by gel filtration (4) as well as studies of the effects of anions on (i) the reduction potential of cytochrome c (5,6), (ii) the JH NMR spectrum of the protein (7), (iii) the chromatographic mobilities of carboxydinitrophenyl cytochromes c, each with a single carboxydinitrophenyl-substituted lysine residue per molecule [monoCDNP-cytochrome(s) c] (8,9), (iv) the interaction of various native and chemically modified cytochromes c with cytochrome c oxidase (10-13, §), cytochrome c peroxidase (14,15), or nonphysiological oxidants and reductants (16)(17)(18)(19)(20)(21)(22), (v) the interaction of phosphate (monitored by 31P NMR) (12, §) or of chloride (monitored by 31C1 NMR) (23) with the protein, and (vi) the oxidation of threonyl residues after the reduction of ferricytochrome c by ferrous ion (22).…”

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confidence: 99%

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Mapping of anion binding sites on cytochrome c by differential chemical modification of lysine residues.

Osheroff¹,

Brautigan²,

Margoliash³

1980

Proc. Natl. Acad. Sci. U.S.A.

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The carbonate binding site on horse cytochrome c was mapped by comparing the yields of carboxydinitrophenyl-cytochromes c, each with a single carboxydinitrophenyl-substituted lysine residue per molecule, when the modification reaction was carried out in the presence and absence of carbonate. The site is located on the "left surface" of the protein and consists of lysine residues 72 and/or 73 as well as 86 and/or 87 (Carbonate Site). Although one of the binding sites for phosphate on cytochrome c (Phosphate Site 1) is located near the carbonate site, the sites are distinctly different since carbonate does not displace bound phosphate, as monitored by 31P NMR. Furthermore, citrate interacts with Phosphate Site I with high affinity, whereas chloride, acetate, borate, and cacodylate have a much lower affinity for this site, if they bind to it at all. The affinity of phosphate for Phosphate Site I (KD = 2 X 10-4 M) is at least 1 order of magnitude higher than it is for other sites of interaction.

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“…AtFd4 shows a very high activity in both of these reactions, combined with a low affinity for both FNR molecules. In this assay, Fd reduces cytochrome c, and the relatively high redox potential of AtFd4 is no barrier to electron transfer, because cytochrome c has an even more positive redox potential of around ϩ250 mV (Margalit and Schejter, 1973).…”

Section: Non-photosynthetic Support Of Redox Metabolismmentioning

confidence: 99%

A Post Genomic Characterization of Arabidopsis Ferredoxins

et al. 2004

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In higher plant plastids, ferredoxin (Fd) is the unique soluble electron carrier protein located in the stroma. Consequently, a wide variety of essential metabolic and signaling processes depend upon reduction by Fd. The currently available plant genomes of Arabidopsis and rice (Oryza sativa) contain several genes encoding putative Fds, although little is known about the proteins themselves. To establish whether this variety represents redundancy or specialized function, we have recombinantly expressed and purified the four conventional [2Fe-2S] Fd proteins encoded in the Arabidopsis genome and analyzed their physical and functional properties. Two proteins are leaf type Fds, having relatively low redox potentials and supporting a higher photosynthetic activity. One protein is a root type Fd, being more efficiently reduced under nonphotosynthetic conditions and supporting a higher activity of sulfite reduction. A further Fd has a remarkably positive redox potential and so, although redox active, is limited in redox partners to which it can donate electrons. Immunological analysis indicates that all four proteins are expressed in mature leaves. This holistic view demonstrates how varied and essential soluble electron transfer functions in higher plants are fulfilled through a diversity of Fd proteins.Ferredoxin (Fd) is a soluble, low M r protein that mediates transfer of one electron from a donor to an acceptor. The redox active center is a [2Fe-2S] cluster that confers a highly negative redox potential on the protein (Ϫ350 to Ϫ450 mV), making Fd a powerful reductant. The [2Fe-2S] cluster is ligated by four highly conserved Cys residues.A broad spectrum of redox metabolism in higher plant plastids involves Fd. Although the name Fd was first used to describe a non-photosynthetic bacterial protein involved in nitrogen fixation (Mortenson et al., 1962), Fd is best known for a photosynthetic role: accepting electrons from photosystem I (PSI) and donating them to the enzyme Fd:NADP ϩ oxidoreductase (FNR) for photoreduction of NADP ϩ (Arnon, 1989). Donation of electrons by Fd has now been demonstrated to many other plastid enzymes essential for cellular processes, including nitrogen assimilation (nitrite reductase), sulfur assimilation (sulfite reductase [SiR]), amino acid synthesis (Glnoxoglutarate amino transferase), fatty acid synthesis (fatty acid desaturase), and redox regulation (Fd: thioredoxin reductase) (Knaff, 1996). In addition to PSI, Fd may be reduced by NADPH oxidation in a reversal of the FNR reaction (Suzuki et al., 1985). This enables Fd-dependent metabolism to continue under non-photosynthetic conditions, such as in root plastids.Fds are present as multiple isoforms in many plants and algae (Bertini et al., 2002). In higher plants, those predominantly expressed in photosynthetic tissues can be crudely divided from those that are not on the basis of primary sequence (Wada et al., 1986). Work using maize (Zea mays) has exposed functional differences between these Fd types; the rate of light-dependent NA...

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Cytochrome c: A Thermodynamic Study of the Relationships among Oxidation State, Ion‐Binding and Structural Parameters

Cited by 209 publications

References 20 publications

Amino acid sequence, haem-iron co-ordination geometry and functional properties of mitochondrial and bacterial c-type cytochromes

Amino acid sequence, haem-iron co-ordination geometry and functional properties of mitochondrial and bacterial c-type cytochromes

Mapping of anion binding sites on cytochrome c by differential chemical modification of lysine residues.

A Post Genomic Characterization of Arabidopsis Ferredoxins

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