The aarC gene responsible for acetic acid assimilation confers acetic acid resistance on acetobacter aceti

Fukaya, Masahiro; Takashima, Hiroshi; Tayama, Kenji; Okumura, Hajime; Kawamura, Yoshiya; Horinouchi, Sueharu; Beppu, Teruhiko

doi:10.1016/0922-338x(93)90192-b

Cited by 46 publications

(35 citation statements)

References 27 publications

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“…SCACT is encoded by aarC. This biochemical function explains the genetic evidence for the essential roles of aarC in acetic acid resistance, assimilation, and oxidation (16,17).…”

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confidence: 99%

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A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti

2008

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Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO 2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO 2 loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels.

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“…SCACT is encoded by aarC. This biochemical function explains the genetic evidence for the essential roles of aarC in acetic acid resistance, assimilation, and oxidation (16,17).…”

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confidence: 99%

“…AarB is predicted to be a basic protein of 154 amino acids with no homologues or known function (16). AarC is required for acetate oxidation and resembles several acyl-coenzyme A (CoA):carboxylate CoA transferases but is not acetyl-CoA synthetase (17).…”

mentioning

confidence: 99%

A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti

2008

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“…The molecular mechanisms conferring acetic acid resistance on Acetobacter aceti have been investigated using acetic acid-sensitive mutants, and the aarA gene encoding citrate synthase and the aarC gene were found to be responsible for acetate assimilation. 3,4) Later, enhanced expression of aconitase was found to lead the acetic acid resistance, 5) and the acetic acid resistance protein AarC was identified as succinylCoA:acetyl-CoA transferase, converting succinyl-CoA and acetate to succinate and acetyl-CoA, which process allows acetic acid to be removed efficiently without substrate-level phosphorylation.…”

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confidence: 99%

Acetic Acid Fermentation ofAcetobacter pasteurianus: Relationship between Acetic Acid Resistance and Pellicle Polysaccharide Formation

Kanchanarach

Theeragool

Inoue

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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“…The overoxidation of acetic acid is caused by increased activity of tricarboxylic acid cycle enzymes and acetyl-coenzyme A synthetase (14) and also by increased NADH oxidase activity in the respiratory chain (unpublished data). The acetate resistance genes isolated from A. aceti mutants encode citrate synthase and a protein involved in acetate assimilation (2,3), and aconitase is increased in the presence of acetic acid in the culture (10). The genes and proteins are involved as part of the acetate assimilating system active during the overoxidation phase.…”

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confidence: 99%

“…For Acetobacter aceti, the isolation of acetic acid-sensitive mutants (2,3) and proteome analysis of acetic acid-induced proteins (10) have been performed without regard for this overoxidation-dependent phenomenon. The overoxidation of acetic acid is caused by increased activity of tricarboxylic acid cycle enzymes and acetyl-coenzyme A synthetase (14) and also by increased NADH oxidase activity in the respiratory chain (unpublished data).…”

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confidence: 99%

Acetobacter aceti Possesses a Proton Motive Force-Dependent Efflux System for Acetic Acid

et al. 2005

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Acetic acid bacteria are obligate aerobes able to oxidize ethanol, sugar alcohols, and sugars into their corresponding acids. Among them, Acetobacter and Gluconacetobacter species have very high ethanol oxidation capacity, leading to accumulation of vast amounts of acetic acid outside the cell. Since these bacteria are able to grow in media with high concentrations of acetic acid, they must possess a specific mechanism such as an efflux pump by which they can resist the toxic effects of acetic acid. In this study, the efflux pump of Acetobacter aceti IFO 3283 was examined using intact cells and membrane vesicles. The accumulation of acetic acid/acetate in intact cells was increased by the addition of a proton uncoupler and/or cyanide, suggesting the presence of an energy-dependent efflux system. To confirm this, right-side-out and inside-out membrane vesicles were prepared from A. aceti IFO 3283, and the accumulation of acetic acid/acetate in the vesicles was examined. Upon the addition of a respiratory substrate, the accumulation of acetic acid/acetate in the right-side-out vesicles was largely decreased, while its accumulation was very much increased in the inside-out vesicles. These respiration-dependent phenomena observed in both types of membrane vesicles were all sensitive to a proton uncoupler. Acetic acid/acetate uptake in the inside-out membrane vesicles was dependent not on ATP but on the proton motive force. Furthermore, uptake was shown to be rather specific for acetic acid and to be pH dependent, because higher uptake was observed at lower pH. Thus, A. aceti IFO 3283 possesses a proton motive force-dependent efflux pump for acetic acid.

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The aarC gene responsible for acetic acid assimilation confers acetic acid resistance on acetobacter aceti

Cited by 46 publications

References 27 publications

A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti

A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti

Acetic Acid Fermentation ofAcetobacter pasteurianus: Relationship between Acetic Acid Resistance and Pellicle Polysaccharide Formation

Acetobacter aceti Possesses a Proton Motive Force-Dependent Efflux System for Acetic Acid

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