Paracoccus denitrificans and the evolutionary origin of the mitochondrion

John, P. S.; Whatley, F. R.

doi:10.1038/254495a0

Cited by 364 publications

(162 citation statements)

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“…Organic acid syntrophy (Fig 4) This hypothesis was the first to be suggested, and was modeled on the modern relationship of the cytoplasm and mitochondria [31][32][33]. The host cell fermented organic matter such as glucose to organic acids such as pyruvate and lactate.…”

Section: Mitochondrial Origin From a Mutualistic Symbiosismentioning

confidence: 99%

Metabolic integration during the evolutionary origin of mitochondria

Searcy

2003

Cell Res

115

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Although mitochondria provide eukaryotic cells with certain metabolic advantages, in other ways they may be disadvantageous. For example, mitochondria produce reactive oxygen species that damage both nucleocytoplasm and mitochondria, resulting in mutations, diseases, and aging. The relationship of mitochondria to the cytoplasm is best understood in the context of evolutionary history. Although it is clear that mitochondria evolved from symbiotic bacteria, the exact nature of the initial symbiosis is a matter of continuing debate. The exchange of nutrients between host and symbiont may have differed from that between the cytoplasm and mitochondria in modern cells. Speculations about the initial relationships include the following.(1) The pre-mitochondrion may have been an invasive, parasitic bacterium. The host did not benefit. (2) The relationship was a nutritional syntrophy based upon transfer of organic acids from host to symbiont. (3) The relationship was a syntrophy based upon H2 transfer from symbiont to host, where the host was a methanogen. (4) There was a syntrophy based upon reciprocal exchange of sulfur compounds. The last conjecture receives support from our detection in eukaryotic cells of substantial H2S-oxidizing activity in mitochondria, and sulfur-reducing activity in the cytoplasm.

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Section: Mitochondrial Origin From a Mutualistic Symbiosismentioning

confidence: 99%

Metabolic integration during the evolutionary origin of mitochondria

Searcy

2003

Cell Res

115

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“…Such a location, which is found for some of the proteins involved in oxidative phosphorylation, the canonical function of aerobic mitochondria, would make a direct link between gene and organelle. To explain the localization of genes of mitochondrial ancestry on host nuclear genomes, it is necessary to posit that they were transferred from the endosymbiont genome to the host nuclear genome during the process of transforming endosymbiont into an organelle ( John & Whatley 1975;Viale & Arakaki 1994). This process has been called endosymbiotic gene transfer and it is still ongoing (Timmis et al 2004).…”

Section: The Demise Of Archezoamentioning

confidence: 99%

“…Consequently, opinions are diverse concerning the ecological context and selective advantages for host and endosymbiont (e.g. John & Whatley 1975;Martin & Mü ller 1998;Cavalier-Smith 2002;Embley & Martin 2006). What does seem well founded is that the resulting host-endosymbiont consortium forged the common ancestor of all of the mitochondrion-containing eukaryotes that are seen today.…”

Section: Introductionmentioning

confidence: 99%

“…Goksoyr 1967;Cavalier-Smith 1983b). A member of this anaerobic eukaryotic community is posited to have subsequently phagocytosed a eubacterium that could carry out aerobic respiration and which subsequently became an endosymbiont ( John & Whatley 1975). The presence of this eubacterial endosymbiont allowed the host to colonize aerobic environments.…”

Section: Introductionmentioning

confidence: 99%

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Multiple secondary origins of the anaerobic lifestyle in eukaryotes

Embley

2006

Phil. Trans. R. Soc. B

111

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Classical ideas for early eukaryotic evolution often posited a period of anaerobic evolution producing a nucleated phagocytic cell to engulf the mitochondrial endosymbiont, whose presence allowed the host to colonize emerging aerobic environments. This idea was given credence by the existence of contemporary anaerobic eukaryotes that were thought to primitively lack mitochondria, thus providing examples of the type of host cell needed. However, the groups key to this hypothesis have now been shown to contain previously overlooked mitochondrial homologues called hydrogenosomes or mitosomes; organelles that share common ancestry with mitochondria but which do not carry out aerobic respiration. Mapping these data on the unfolding eukaryotic tree reveals that secondary adaptation to anaerobic habitats is a reoccurring theme among eukaryotes. The apparent ubiquity of mitochondrial homologues bears testament to the importance of the mitochondrial endosymbiosis, perhaps as a founding event, in eukaryotic evolution. Comparative study of different mitochondrial homologues is needed to determine their fundamental importance for contemporary eukaryotic cells.

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“…The membrane-bound form of the P. denitrificans enzyme in whole cells is characterized by electron paramagnetic resonance (EPR) signals like those observed in mammalian mitochondria (10). P. denitrificans appears to be the closest bacterial homologue to this organelle (11,12), and its SQR is amenable to molecular genetic techniques. The purification and basic biochemical properties of SQR from this bacterium have also been reported (6).…”

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confidence: 99%

Electron Paramagnetic Resonance Studies of Succinate:Ubiquinone Oxidoreductase from Paracoccus denitrificans

Waldeck¹,

Stowell²,

Lee³

et al. 1997

Journal of Biological Chemistry

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Electron paramagnetic resonance (EPR) studies of succinate:ubiquinone oxidoreductase (SQR) from Paracoccus denitrificans have been undertaken in the purified and membrane-bound states. Spectroscopic "signatures" accounting for the three iron-sulfur clusters (2Fe-2S, 3Fe-4S, and 4Fe-4S), cytochrome b, flavin, and protein-bound ubisemiquinone radicals have been obtained in air-oxidized, succinate-reduced, and dithionite-reduced preparations at 4 -10 K. Spectra obtained at 170 K in the presence of excess succinate showed a signal typical of that of a flavin radical, but superimposed with another signal. The superimposed signal originated from two bound ubisemiquinones, as shown by spectral simulations. Power saturation measurements performed on the air-oxidized enzyme provided evidence for a weak magnetic dipolar interaction operating between the oxidized 3Fe-4S cluster and the oxidized cytochrome b. Power saturation experiments performed on the succinate-and dithionite-reduced forms of the enzyme demonstrated that the 4Fe-4S cluster is coupled weakly to both the 2Fe-2S and the 3Fe-4S clusters. Quantitative interpretation of these power saturation experiments has been achieved through redox calculations. They revealed that a spin-spin interaction between the reduced 3Fe-4S cluster and the cytochrome b (oxidized) may also exist. These findings form the first direct EPR evidence for a close proximity ( 2 nm) of the high potential 3Fe-4S cluster, situated in the succinate dehydrogenase part of the enzyme, and the low potential, low spin b-heme in the membrane anchor of the enzyme.Succinate:ubiquinone oxidoreductase, SQR, 1 is the only membrane-bound enzyme in the tricarboxylic acid cycle. As "complex II," it performs the two-electron oxidation of succinate to produce fumarate, while transferring the electrons to quinone (Q) to yield quinol (QH 2 ). The reverse process is mediated by quinol:fumarate oxidoreductases (QFR), which occur in anaerobic and some facultative organisms. The two enzymes are related and are capable of catalyzing their respective reverse reactions under suitable conditions (1, 2).SQR contains three or four polypeptides depending on the organism. The largest subunit, a flavoprotein, contains the dicarboxylate binding site and one flavin moiety (FAD); the latter is covalently bound in most cases. The iron-sulfur protein is intermediate in size and contains three iron-sulfur clusters of type 2Fe-2S, 4Fe-4S, and 3Fe-4S, often referred to as S-1, S-2, and S-3, respectively, in the case of SQR. These two hydrophilic subunits protrude into the cytosol (prokaryotic enzyme) or the mitochondrial matrix (eukaryotic enzyme), and together catalyze the succinate dehydrogenase activity of the enzyme. They are anchored to the membrane by one or two hydrophobic quinone polypeptides (QP), which may contain zero, one, or two b-heme(s). These anchoring subunits confer reactivity with the bound Qs; for SQR from bovine heart (3, 4) and a variety of higher plants (5), the existence of two Q sites has been established. S...

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Paracoccus denitrificans and the evolutionary origin of the mitochondrion

Cited by 364 publications

References 52 publications

Metabolic integration during the evolutionary origin of mitochondria

Metabolic integration during the evolutionary origin of mitochondria

Multiple secondary origins of the anaerobic lifestyle in eukaryotes

Electron Paramagnetic Resonance Studies of Succinate:Ubiquinone Oxidoreductase from Paracoccus denitrificans

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