Mass Spectra of Ubiquinones and Ubiquinols

Rf, Muraca; Js, Whittick; Gd, Daves; Friis, Palle; Folkers, Karl

doi:10.1021/ja00982a038

Cited by 72 publications

(27 citation statements)

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“…They corresponded to the molecular ions of plastoquinone and plastoquinol, both containing again 9 CD 3 groups. Indeed, analysis of prenylated quinones is often hampered by the reduction of the quinone inside the source of the mass spectrometer, a process that is unavoidable and hardly reproducible (42). The high level of incorporation was confirmed in the mass spectra from all three feeding experiments performed with [1,1,1,4-2 H 4 ]DX.…”

Section: -Deoxy-d-xylulose Reverses Inhibition By Mevinolin Of Cell mentioning

confidence: 80%

Cross-talk between the Cytosolic Mevalonate and the Plastidial Methylerythritol Phosphate Pathways in Tobacco Bright Yellow-2 Cells

Hemmerlin

Hoeffler

Meyer

et al. 2003

Journal of Biological Chemistry

392

296

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Section: -Deoxy-d-xylulose Reverses Inhibition By Mevinolin Of Cell mentioning

confidence: 80%

Cross-talk between the Cytosolic Mevalonate and the Plastidial Methylerythritol Phosphate Pathways in Tobacco Bright Yellow-2 Cells

Hemmerlin

Hoeffler

Meyer

et al. 2003

Journal of Biological Chemistry

392

296

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“…5), which revealed the presence in lipid extracts of the wild type and coq10 null mutant of the correct molecular ion with a mass/charge ratio (m/z) of Q 6 at 591.4. This ion produced characteristic fragment ions including the predominant base peak and tropyllium ion at m/z 197, a definitive breakdown product of Q 6 (35). The concentration of Q 6 in the mutant was estimated to be 3.32 g/mg of mitochondrial protein (Fig.…”

Section: By⌬coq10 and W303⌬coq10mentioning

confidence: 99%

The Saccharomyces cerevisiae COQ10 Gene Encodes a START Domain Protein Required for Function of Coenzyme Q in Respiration

Barros

Johnson

Gin

et al. 2005

Journal of Biological Chemistry

163

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Deletion of the Saccharomyces cerevisiae gene YOL008W, here referred to as COQ10, elicits a respiratory defect as a result of the inability of the mutant to oxidize NADH and succinate. Both activities are restored by exogenous coenzyme Q 2 . Respiration is also partially rescued by COQ2, COQ7, or COQ8/ABC1, when these genes are present in high copy. Unlike other coq mutants, all of which lack Q 6 , the coq10 mutant has near normal amounts of Q 6 in mitochondria. Coq10p is widely distributed in bacteria and eukaryotes and is homologous to proteins of the "aromatic-rich protein family" Pfam03654 and to members of the START domain superfamily that have a hydrophobic tunnel implicated in binding lipophilic molecules such as cholesterol and polyketides. Analysis of coenzyme Q in polyhistidine-tagged Coq10p purified from mitochondria indicates the presence 0.032-0.034 mol of Q 6 /mol of protein. We propose that Coq10p is a Q 6 -binding protein and that in the coq10 mutant Q 6 it is not able to act as an electron carrier, possibly because of improper localization.Coenzyme Q (ubiquinone) is an essential electron carrier of the mitochondrial respiratory chain. Its main function is to accept electrons from the NADH-and succinate-coenzyme Q reductases and to donate them to the bc 1 complex (1). Biosynthesis of coenzyme Q in eukaryotes occurs in mitochondria. The benzoquinone ring of coenzyme Q 6 (Q 6 ) of Saccharomyces cerevisiae has a polyprenyl side chain with six isoprenoid units (2). At least nine yeast nuclear genes (COQ1-9) defined by nine complementation groups of a pet 3 mutant collection have been inferred to participate in the synthesis of Q 6 based on the biochemical properties of the mutant mitochondria (3, 4). Mutations in each of the nine genes block the NADH and succinate-cytochrome c reductase activities of mitochondria, which can be restored by addition of coenzyme Q 2 (5). Additionally, coq mutants lack Q 6 and coq3, coq4, coq5, coq6, coq7, coq8/abc1, and coq9 mutants accumulate 3-hexaprenyl-4-hydroxybenzoic acid, an early intermediate in Q 6 biosynthesis (Refs. 4 and 6 -13, see Ref. 11 for details of the pathway in yeast). Except for demethoxy-Q 6 , which accumulates in certain coq7 point mutants (7,14), other intermediates of the pathway are not detected in coq mutants (6 -12). These observations indicate that the pathway is stringently regulated and/or that most of the intermediates are degraded when biosynthesis of Q 6 is arrested. COQ gene products are located in, or are peripherally associated with the inner membrane of mitochondria (9 -15) where they constitute a pathway that is similar to but diverges from the one in bacteria in at least two steps (16,17).In the present study we report a novel phenotype displayed by mutants with a deletion of reading frame YOL008W, which we have named COQ10. The coq10 mutant is similar to other coq mutants in which optimal oxidation of NADH and succinate by isolated mitochondria depends on addition of coenzyme Q 2 . Unlike the coq mutants, which lack Q 6 , the coq...

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“…The mass spectra of all the quinone samples showed intense peaks at m/e 235 and 197 derived from the pyrilium and benzelium (Muraca et al, 1967). The mass spectra in the high mass region contained strong peaks corresponding to the molecular ion (M+).…”

Section: R E S U L T Smentioning

confidence: 99%

Ubiquinone, Fatty acid and DNA Base Composition Determination as a Guide to the Taxonomy of the Genus Thiobacillus

1982

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Facultatively chemolithotrophic thiobacilli, Thiobacillus perometabolis THI 022, Thiobacillus sp. A2, Thiobacillus novellus, Thiobacillus organoparus and Thiobacillus acidophilus, had ubiquinones with 10 isoprene units (Q-10) (group I). These species also had [octadecenoic acid (18 : 1) + cyclopropane acid of CI9 (19, , , )] as major non-hydroxylated fatty acids. The organisms, except T. novellus, contained 3-hydroxydecanoic acid (3-OH 10 : 0) or 3-hydroxytetradecanoic acid (3-OH 14 : 0) as hydroxy fatty acids. DNA base compositions of these species were 63 to 68 mol% G + C. Other facultatively chemolithotrophic thiobacilli, including T. perometabolis THI 023, Thiobacillus delicatus and Thiobacillus intermedius with or without [ 18 : 1 + 19, , , ] as major non-hydroxylated fatty acids. The species of group I11 contained 3-OH 12:O and some had 3-OH 10:0 when grown at neutral pH and 3-OH 14 :O in acidophilic conditions. DNA base compositions of these organisms ranged from 5 1 to 64 mol% G + C. Chemotaxonomic characteristics would seem to be useful for the identification and the classification of thiobacilli.

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Mass Spectra of Ubiquinones and Ubiquinols

Cited by 72 publications

References 0 publications

Cross-talk between the Cytosolic Mevalonate and the Plastidial Methylerythritol Phosphate Pathways in Tobacco Bright Yellow-2 Cells

Cross-talk between the Cytosolic Mevalonate and the Plastidial Methylerythritol Phosphate Pathways in Tobacco Bright Yellow-2 Cells

The Saccharomyces cerevisiae COQ10 Gene Encodes a START Domain Protein Required for Function of Coenzyme Q in Respiration

Ubiquinone, Fatty acid and DNA Base Composition Determination as a Guide to the Taxonomy of the Genus Thiobacillus

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