Cytochrome c2 is essential for electron transfer to nitrous oxide reductase from physiological substrates in Rhodobacter capsulatus and can act as an electron donor to the reductase in vitro

Richardson, David J.; Bell, Louise C.; McEwan, Alastair G.; Jackson, John L.; Ferguson, Stuart J.

doi:10.1111/j.1432-1033.1991.tb16170.x

Cited by 54 publications

(34 citation statements)

References 33 publications

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“…In R. capsulatus MTG4S4 the record of respiration measured by the nitric oxide electrode was monophasic, resembling the parent strain in the presence of acetylene. This is because cytochrome c2 has been found to be an obligatory component for nitrous oxide respiration (Richardson et al, 1991) which, as described earlier, accounts for the second phase of the electrode response with cells. The cytochrome bcl complex was still operative in the mutant since myxothiazol was observed to give partial but considerable inhibition (Table 2).…”

Section: Methodsmentioning

confidence: 98%

Identification of nitric oxide reductase activity in Rhodobacter capsulatus: the electron transport pathway can either use or bypass both cytochrome c2 and the cytochrome bc1 complex

Bell

Richardson²,

Ferguson³

1992

Journal of General Microbiology

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Several strains of Rhohbaeter capsufatus have been shown to possess a nitric oxide reductase activity (reaction product nitrous oxide) after anaerobic phototrophic growth, but not after aerobic growth. The reductase is associated with the cytoplasmic membrane and electrons can reach the enzyme via the cytochrome bel complex. However, use of appropriate strains has shown that neither the latter, cytochrome c2 nor cytochrome c' is essential for the reduction of nitric oxide. Inhibition by myxothiazol of nitric oxide reduction in a strain that lacks a cytochrome c2 establishes that in phototrophically grown R. capsufatus the cytochrome bel complex is able to transfer electrons to an acceptor that is alternative to cytochrome c2. Electron transport to nitric oxide from NADH or succinate generated a membrane potential. When isoascorbate plus 2,3,5,6-tetramethyl-p-phenylenediamine (DAD) was the electron donor a membrane potential was not generated. This observation implies that nitric oxide is reduced at the periplasmic surface of the membrane and that the reductase is not proton translocating.

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Section: Methodsmentioning

confidence: 98%

Identification of nitric oxide reductase activity in Rhodobacter capsulatus: the electron transport pathway can either use or bypass both cytochrome c2 and the cytochrome bc1 complex

Bell

Richardson²,

Ferguson³

1992

Journal of General Microbiology

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“…On the other hand, it is not known whether cyt c 2 and cyt c y are used preferentially under yet to be determined specific growth conditions or whether two physically distinct pools of RC or cyt cbb 3 oxidase "committed" to interact with different electron carriers exist in various species, including R. capsulatus. Finally, note that cyt c 2 is also an essential electron carrier in vivo during anaerobic respiratory growth in the presence of nitrous oxide as an electron sink (35). In any event, clearly, Rhodobacter species continue to provide an attractive model system for understanding how the different electron carriers function to support maximal electron transport during various growth modes.…”

Section: Discussionmentioning

confidence: 99%

Cytochrome c(y) of Rhodobacter capsulatus is attached to the cytoplasmic membrane by an uncleaved signal sequence-like anchor

et al. 1997

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During the photosynthetic growth of Rhodobacter capsulatus, electrons are conveyed from the cytochrome (cyt) bc 1 complex to the photochemical reaction center by either the periplasmic cyt c 2 or the membrane-bound cyt c y . Cyt c y is a member of a recently established subclass of bipartite c-type cytochromes consisting of an amino (N)-terminal domain functioning as a membrane anchor and a carboxyl (C)-terminal domain homologous to cyt c of various sources. Structural homologs of cyt c y have now been found in several bacterial species, including Rhodobacter sphaeroides. In this work, a C-terminally epitope-tagged and functional derivative of R. capsulatus cyt c y was purified from intracytoplasmic membranes to homogeneity. Analyses of isolated cyt c y indicated that its spectral and thermodynamic properties are very similar to those of other c-type cytochromes, in particular to those from bacterial and plant mitochondrial sources. Amino acid sequence determination for purified cyt c y revealed that its signal sequence-like N-terminal portion is uncleaved; hence, it is anchored to the membrane. To demonstrate that the N-terminal domain of cyt c y is indeed its membrane anchor, this sequence was fused to the N terminus of cyt c 2 . The resulting hybrid cyt c (MA-c 2 ) remained membrane bound and was able to support photosynthetic growth of R. capsulatus in the absence of the cyt c y and c 2 . Therefore, cyt c 2 can support cyclic electron transfer during photosynthetic growth in either a freely diffusible or a membraneanchored form. These findings should now allow for the first time the comparison of electron transfer properties of a given electron carrier when it is anchored to the membrane or is freely diffusible in the periplasm.

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“…In the case of N 2 OR isolated from Rhodobacter capsulatus, Rhodobacter sphaeroides f. sp. denitrificans, and Paracoccus pantotrophus [37,82,83], the physiological donor is a periplasmic c-type cytochrome, but Paracoccus pantotrophus N 2 OR can also accept electrons from a periplasmic type 1 copper protein, pseudoazurin [37], and from the mitochondrial horse heart cytochrome c [81]. Bovine heart cytochrome c is able to reduce Achromobacter cycloclastes N 2 OR [84], but its physiological electron donor is pseudoazurin [85].…”

Section: Catalytic Properties Of Cuz and Reaction Intermediatesmentioning

confidence: 99%

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

et al. 2011

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This review focuses on the novel CuZ center of nitrous oxide reductase, an important enzyme owing to the environmental significance of the reaction it catalyzes, reduction of nitrous oxide, and the unusual nature of its catalytic center, named CuZ. The structure of the CuZ center, the unique tetranuclear copper center found in this enzyme, opened a novel area of research in metallobiochemistry. In the last decade, there has been progress in defining the structure of the CuZ center, characterizing the mechanism of nitrous oxide reduction, and identifying intermediates of this reaction. In addition, the determination of the structure of the CuZ center allowed a structural interpretation of the spectroscopic data, which was supported by theoretical calculations. The current knowledge of the structure, function, and spectroscopic characterization of the CuZ center is described here. We would like to stress that although many questions have been answered, the CuZ center remains a scientific challenge, with many hypotheses still being formed.

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Cytochrome c₂ is essential for electron transfer to nitrous oxide reductase from physiological substrates in Rhodobacter capsulatus and can act as an electron donor to the reductase in vitro

Cited by 54 publications

References 33 publications

Identification of nitric oxide reductase activity in Rhodobacter capsulatus: the electron transport pathway can either use or bypass both cytochrome c2 and the cytochrome bc1 complex

Identification of nitric oxide reductase activity in Rhodobacter capsulatus: the electron transport pathway can either use or bypass both cytochrome c2 and the cytochrome bc1 complex

Cytochrome c(y) of Rhodobacter capsulatus is attached to the cytoplasmic membrane by an uncleaved signal sequence-like anchor

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

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