Properties and function of the two hemes in Pseudomonas cytochrome c peroxidase

Ellfolk, Nils; Rönnberg, Marjaana; Aasa, Roland; Andréasson, Lars-Erik; Vänngård, Tore

doi:10.1016/0167-4838(83)90413-2

Cited by 90 publications

(99 citation statements)

References 33 publications

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“…Evidence for the presence of interactions between the different centres of a multiredox centre electron carrier has been reported earlier, namely for cytochrome c oxidase [48 -521, cytochrome c peroxidase [53], cytochrome h dimer [54], succinate dehydrogenase [55] and xanthine oxidase [41]. Several kinds of interaction have been postulated : redox interaction, in which the spectral characteristics [56] and the oxidation-reduction potential of one centre is affected by the oxidation state of its neighbours [51] and magnetic interactions between the different paramagnetic centres [57].…”

Section: Discussionmentioning

confidence: 81%

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃

Santos¹,

Moura²,

Moura³

et al. 1984

European Journal of Biochemistry

162

132

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The proton NMR spectra of the tetrahaem cytochrome c3 from Desulfovibrio gigas were examined while varying the pH and the redox potential. The analysis of the N M R reoxidation pattern was based on a model for the electron distribution between the four haems that takes into account haem-haem redox interactions. The intramolecular electron exchange is fast on the N M R time scale (larger than lo5 s-I ) . The NMR data concerning the pH dependence of the chemical shift of haem methyl resonances in different oxidation steps and resonance intensities are not compatible with a non-interacting model and can be explained assuming a redox interaction between the haems. A complete analysis at pH* = 7.2 and 9.6, shows that the haem-haem interacting potentials cover a range from -50 mV to +60 mV. The midpoint redox potentials of some of the haems, as well as some of their interacting potentials, are pH-dependent. The physiological relevance of the modulation of the haem midpoint redox potentials by both the pH and the redox potential of the solution is discussed.Cy tochromc c3 ( M , 13 000) is a multihaem protein found in anaerobic sulfate-reducing bacteria belonging to the genus Desulfuvibrin. Each molecule contains four haems with an unusually low redox potential. They are covalently attached to the polypeptide chain by thioether linkages provided by cysteinyl residues and two histidines are used as axial ligands.Cytochrome [39] have been applied to elucidate the mechanism of electron transfer in cytochrome c3.The midpoint redox potentials of the four haems are different, in general. EPR measurements coupled with potentiometric titrations were performed to determine the midpoint redox potentials of the individual haems of D. gigas cytochrome c3 [27] (-235mV, -235mV, -306mV, -315mV) [35]; the experiments were fitted by digital simulations and the best fit was obtained with -220mV, -272mV, -292mV, and --310mV, for the four macroscopic midpoint redox potentials. Bianco et al. [36] reported values of -170mV, -310mV, -360mV and -400mV for the half-wave potentials of cytochrome c3 from D. desidfuricans (Norway 4). However. it should be emphasized that the individual potentials obtained from electrochemical studies are macroscopic rather than microscopic parameters and can not be compared directly with the values obtained from EPR measurements. Furthermore, thc EPR measurements

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Section: Discussionmentioning

confidence: 81%

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃

Santos¹,

Moura²,

Moura³

et al. 1984

European Journal of Biochemistry

162

132

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“…The amino acid sequence of RoxA (71.5 kDa for the mature protein) harbours two motifs for covalently attached haems (CXXCH) and has an additional approximately 20 amino acid-long sequence that is conserved in CCPs. This amino acid sequence includes a conserved histidine residue in the consensus sequence 'P**H 517 NGSVP', where an asterisk signifies an amino acid with a hydrophobic side chain (Jendrossek & Reinhardt, 2003 Ellfolk et al, 1983;Shimizu et al, 2001). These similarities suggest that RoxA is somehow related to bacterial CCPs and that His 517 could have a role in electron transfer between the two centres.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic properties of rubber oxygenase RoxA from Xanthomonas sp., a new type of dihaem dioxygenase

et al. 2010

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Natural rubber [poly-(cis-1,4-isoprene)] is cleaved to by rubber oxygenase A (RoxA) isolated from Xanthomonas sp. RoxA has two c-type haem centres that show two distinct a-bands at 549 and 553 nm in the dithionite-reduced state. A wellresolved midpoint potential (E 0 9) of -65 mV was determined for one haem by spectrophotometric titrations in the absence of dioxygen with dithionite and ferricyanide as reductant and oxidant, respectively. The midpoint potential of the second haem was not resolvable (E 0 9 about "130 to -160 mV). One of the two haems was reduced by NADH (549 nm a-band), similar to bacterial dihaem peroxidases. Evidence for an electron transfer between the two haems was provided by slow reduction of the second haem (553 nm a-band) upon incubation of the partially reduced enzyme at room temperature. Addition of imidazole or related compounds to RoxA led to UV/vis spectral features similar to those observed for partially reduced RoxA. Notably, reduction of RoxA with dithionite or NADH, or binding of compounds such as imidazole, resulted in a reversible inactivation of the enzyme, unlike dihaem peroxidases. In line with this result, RoxA did not show any peroxidase activity. EPR spectra of RoxA as isolated showed two low-spin Fe(III) haem centres, with apparent g-values of 3.39, 3.09, 2.23, 1.92 and 1.50. A weak signal in the g56 region resulting from a high-spin Fe(III) haem was also observed with a preparation-dependent intensity that disappeared in the presence of imidazole. Attempts to provide spectroscopic evidence for binding of the natural substrate (polyisoprene latex) to RoxA failed. However, experimental data are presented that RoxA is able to subtract redox equivalents from its substrate or from model compounds. In conclusion, RoxA is a novel type of dihaem dioxygenase with features clearly different from classical cytochrome c peroxidases.

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“…aeruginosa and Paracoccus pantotrophus (5,8,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Spectroscopic studies of these enzymes suggest the existence of a complex reaction mechanism that involves changes in the redox and spin states of the heme groups.…”

mentioning

confidence: 99%

Structural and Mutagenesis Studies on the Cytochrome c Peroxidase from Rhodobacter capsulatus Provide New Insights into Structure-Function Relationships of Bacterial Di-heme Peroxidases

Smet

Savvides

Horen

et al. 2006

Journal of Biological Chemistry

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Cytochrome c peroxidases (CCP) play a key role in cellular detoxification by catalyzing the reduction of hydrogen peroxide to water. The di-heme CCP from Rhodobacter capsulatus is the fastest enzyme (1060 s ؊1 ), when tested with its physiological cytochrome c substrate, among all di-heme CCPs characterized to date and has, therefore, been an attractive target to investigate structure-function relationships for this family of enzymes. Here, we combine for the first time structural studies with site-directed mutagenesis and spectroscopic studies of the mutant enzymes to investigate the roles of amino acid residues that have previously been suggested to be important for activity. The crystal structure of R. capsulatus at 2.7 Å in the fully oxidized state confirms the overall molecular scaffold seen in other di-heme CCPs but further reveals that a segment of about 10 amino acids near the peroxide binding site is disordered in all four molecules in the asymmetric unit of the crystal. Structural and sequence comparisons with other structurally characterized CCPs suggest that flexibility in this part of the molecular scaffold is an inherent molecular property of the R. capsulatus CCP and of CCPs in general and that it correlates with the levels of activity seen in CCPs characterized, thus, far. Mutagenesis studies support the spin switch model and the roles that Met-118, Glu-117, and Trp-97 play in this model. Our results help to clarify a number of aspects of the debate on structure-function relationships in this family of bacterial CCPs and set the stage for future studies.

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Properties and function of the two hemes in Pseudomonas cytochrome c peroxidase

Cited by 90 publications

References 33 publications

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃

Spectroscopic properties of rubber oxygenase RoxA from Xanthomonas sp., a new type of dihaem dioxygenase

Structural and Mutagenesis Studies on the Cytochrome c Peroxidase from Rhodobacter capsulatus Provide New Insights into Structure-Function Relationships of Bacterial Di-heme Peroxidases

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Properties and function of the two hemes in Pseudomonas cytochrome c peroxidase

Cited by 90 publications

References 33 publications

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c3

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c3

Spectroscopic properties of rubber oxygenase RoxA from Xanthomonas sp., a new type of dihaem dioxygenase

Structural and Mutagenesis Studies on the Cytochrome c Peroxidase from Rhodobacter capsulatus Provide New Insights into Structure-Function Relationships of Bacterial Di-heme Peroxidases

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NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃

NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c₃