Respiratory Electron Transfer Chains

Dutton, P. Leslie; Chen, X.; Page, Christopher; Huang, Steve S.; Ohnishi, Tomo̧ko; Moser, Christopher C.

doi:10.1007/978-94-011-5133-7_1

Cited by 17 publications

(6 citation statements)

References 28 publications

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“…However, theoretical calculations indicate that this thermodynamic barrier presents no significant obstacle to fast electron transfer [57]. Furthermore, in Sfc the microscopic redox potentials of the haem groups are much more similar when compared with several cases reported in the literature, namely for membrane-bound fumarate reductases ( [59] and references therein), hydrogenases [57,60], Rhodopseudomonas iridis cytochromes [57,61] and mitochondrial succinate dehydrogenases [58]. In Sffcc $ a much smaller endergonic electron transfer step is needed for the electron transfer within the chain of redox cofactors.…”

Section: Figure 6 Macroscopic Reduction Potentials For Sfc Calculatedmentioning

confidence: 57%

“…As pointed out previously, within the cytochrome domain of Sffcc $ one endergonic electron transfer step is included along the chain of redox centres. This is also found in the membranebound fumarate reductases [55,56], in hydrogenases [57] and in mitochondrial succinate dehydrogenases [58]. However, theoretical calculations indicate that this thermodynamic barrier presents no significant obstacle to fast electron transfer [57].…”

Section: Figure 6 Macroscopic Reduction Potentials For Sfc Calculatedmentioning

confidence: 89%

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Thermodynamic characterization of a tetrahaem cytochrome isolated from a facultative aerobic bacterium, Shewanella frigidimarina: a putative redox model for flavocytochrome c3

Pessanha

Louro

Correia

et al. 2003

Biochemical Journal

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The facultative aerobic bacterium Shewanella frigidimarina produces a small c-type tetrahaem cytochrome (86 residues) under anaerobic growth conditions. This protein is involved in the respiration of iron and shares 42% sequence identity with the N-terminal domain of a soluble flavocytochrome, isolated from the periplasm of the same bacterium, which also contains four c -type haem groups. The thermodynamic properties of the redox centres and of an ionizable centre in the tetrahaem cytochrome were determined using NMR and visible spectroscopy techniques. This is the first detailed thermodynamic study performed on a tetrahaem cytochrome isolated from a facultative aerobic bacterium and reveals that this protein presents unique features. The redox centres have negative and different redox potentials, which are modulated by redox interactions between the four haems (covering a range of 8-56 mV) and by redox-Bohr interactions between the haems and an ionizable centre (-4 to -36 mV) located in close proximity to haem III. All of the interactions between the five centres are clearly dominated by electrostatic effects and the microscopic reduction potential of haem III is the one most affected by the oxidation of the other haems and by the protonation state of the molecule. Altogether, this study indicates that the tetrahaem cytochrome isolated from S. frigidimarina (Sfc) has the thermodynamic properties to work as an electron wire between its redox partners. Considering the high degree of sequence identity between Sfc and the cytochrome domain of flavocytochrome c(3), the structural similarities of the haem core, and that the macroscopic potentials are also identical, the results obtained in this work are rationalized in order to put forward a putative redox model for flavocytochrome c(3).

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Section: Figure 6 Macroscopic Reduction Potentials For Sfc Calculatedmentioning

confidence: 57%

Section: Figure 6 Macroscopic Reduction Potentials For Sfc Calculatedmentioning

confidence: 89%

Thermodynamic characterization of a tetrahaem cytochrome isolated from a facultative aerobic bacterium, Shewanella frigidimarina: a putative redox model for flavocytochrome c3

Pessanha

Louro

Correia

et al. 2003

Biochemical Journal

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“…Now a single gamma factor can be defined for each centre [Eq. (10)] and the superscript st used to specify individual microsteps can be dropped:…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, the driving force, DG i , for ET reactions in biological systems and the interaction energies, I ij F, are typically much smaller than the reorganisation energy l i . [10] Thus, Equation (9) can be approximated by Equation (12), in which s ij depends solely on the s ij % exp I ij F…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Control of Electron Transfer Rates in Multicentre Redox Proteins

Catarino

Turner

2001

ChemBioChem

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In the analysis of kinetic data from multicentre redox proteins, it is essential to distinguish between the observable macroscopic rate constants and the structurally relevant microscopic properties. This distinction is complicated by the existence of interactions between centres. The problem is illustrated by the case of two interacting redox centres and generalised for the analysis of stopped-flow kinetic data for the reduction of cytochrome c(3), in which four redox centres and at least one proteolytic centre are mutually interacting. It is shown that fast intramolecular electron transfer, which is typical of many multicentre redox proteins, and, where present, fast proton exchange, ensure that only N rate constants can be measured for a protein with N redox centres. The equations that relate the observable macroscopic rate constants to the microscopic rate constants of individual centres depend on a set of parameters that can be approximated by using the Marcus theory of electron transfer together with a set of reasonable assumptions. The results are tested by fitting experimental data for the reduction of cytochrome c(3) by sodium dithionite, including its pH dependence.

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“…However, it is possible to find several examples where this is not the case. For example, significantly "uphill" reaction steps occur in the sequential ET reactions that are catalyzed by hydrogenase (30), nitrate reductase (31), the Rhodopseudomonas Viridis tetraheme cytochrome (32), and membrane-bound respiratory chains (33). By examining the effects of the P94F mutation on the rate and extent of ET through the MADH-amicyanincytochrome c-551i complex, it was possible to experimentally determine the consequences of engineering a significantly uphill ET step in a naturally occurring ET chain.…”

Section: Discussionmentioning

confidence: 99%

Effects of Engineering Uphill Electron Transfer into the Methylamine Dehydrogenase−Amicyanin−Cytochrome c-551i Complex

Sun

Davidson

2003

Biochemistry

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Within the methylamine dehydrogenase-amicyanin-cytochrome c-551i complex, electrons are transferred from tryptophan tryptophylquinone (TTQ) to heme via the type I copper center of amicyanin. Mutation of Pro94 of amicyanin to Phe increases the redox potential of the copper center within the protein complex by approximately 195 mV. This introduces a large energy barrier for the second electron transfer (ET) step in this three-protein ET chain. As a consequence of this mutation, the ET rate from TTQ to copper exhibits about a 6-fold increase and the ET rate from copper to heme exhibits about a 100-fold decrease. These changes in ET rate are consistent with the predictions of Marcus theory. Temperature dependence studies of these reactions indicate that the reorganization energies for the ET to and from the copper center are unchanged by the P94F mutation, despite the large change in redox potential that it causes. Steady-state kinetic studies indicate that despite the large energy barrier for the ET from copper to heme, methylamine-dependent reduction of heme by the three-protein complex with P94F amicyanin goes to completion. The turnover number for this steady-state reaction, however, is decreased 50-fold relative to that of the native complex. As a consequence of the P94F mutation, the rate constant for the unfavorable uphill ET reaction from copper to heme has become the rate-limiting step in the overall reaction. The evolutionary implications of the effects of this mutation on the function of this naturally occurring simple ET chain are discussed.

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Respiratory Electron Transfer Chains

Cited by 17 publications

References 28 publications

Thermodynamic characterization of a tetrahaem cytochrome isolated from a facultative aerobic bacterium, Shewanella frigidimarina: a putative redox model for flavocytochrome c3

Thermodynamic characterization of a tetrahaem cytochrome isolated from a facultative aerobic bacterium, Shewanella frigidimarina: a putative redox model for flavocytochrome c3

Thermodynamic Control of Electron Transfer Rates in Multicentre Redox Proteins

Effects of Engineering Uphill Electron Transfer into the Methylamine Dehydrogenase−Amicyanin−Cytochrome c-551i Complex

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