Excess Production of<i>Bacillus subtilis</i>Quercetin 2,3-Dioxygenase Affects Cell Viability in the Presence of Quercetin

Hirooka, Kazutake; Fujita, Yuki

doi:10.1271/bbb.90928

Cited by 20 publications

(21 citation statements)

References 29 publications

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“…These metabolites can be further transformed into their O -methyl metabolites (Chadwick, George, Claxton, 1992). The enzymatic release of protocatechuic acid from quercetin can be mediated by fungal and bacterial quercetin dioxygenases, also referred to as quercetinases (Hirooka, Fujita, 2010; Schaab, Barney, Francisco, 2006) (Table 1). They may contain iron, copper, or manganese in their catalytic site (Sun, Huang, Li et al, 2015).…”

Section: Carbon-carbon Cleavage Reactionsmentioning

confidence: 99%

The chemistry of gut microbial metabolism of polyphenols

2016

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Gut microbiota contribute to the metabolism of dietary polyphenols and affect the bioavailability of both the parent polyphenols and their metabolites. Although there is a large number of reports of specific polyphenol metabolites, relatively little is known regarding the chemistry and enzymology of the metabolic pathways utilized by specific microbial species and taxa, which is the focus of this review. Major classes of dietary polyphenols include monomeric and oligomeric catechins (proanthocyanidins), flavonols, flavanones, ellagitannins, and isoflavones. Gut microbial metabolism of representatives of these polyphenol classes can be classified as A- and C-ring cleavage (retro Claisen reactions), C-ring cleavage mediated by dioxygenases, dehydroxylations (decarboxylation or reduction reactions followed by release of H2O molecules), and hydrogenations of alkene moieties in polyphenols, such as resveratrol, curcumin, and isoflavones (mediated by NADPH-dependent reductases). The qualitative and quantitative metabolic output of the gut microbiota depends to a large extent on the metabolic capacity of individual taxa, which emphasizes the need for assessment of functional analysis in conjunction with determinations of gut microbiota compositions.

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Section: Carbon-carbon Cleavage Reactionsmentioning

confidence: 99%

The chemistry of gut microbial metabolism of polyphenols

2016

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“…24) Further detail characterization revealed that this enzyme is also able to convert other flavonols, such as fisetin, tamarixetin, and galangin, to the corresponding depsides by a similar C-ring cleavage reaction, although its catalytic activity toward fisetin is relatively low. 25) In contrast to qdoI, there is little information about yxaH, except that it is predicted to encode a membrane protein by the sequence information. The qdoR (formerly yxaF) gene encoding the TetR-type transcriptional factor is located immediately upstream of the qdoI-yxaH operon and oriented in the same direction as qdoI-yxaH.…”

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confidence: 99%

“…In addition, we demonstrated that the sensitivity of the mutant B. subtilis strain toward quercetin was quenched by the repression of qdoI by the ectopically introduced lmrA or qdoR gene. 25) Although primary role of QdoI is detoxification of flavonols including quercetin, the excess QdoI activity appears rather harmful in the presence of quercetin, causing rapid production of PCA, apparently more toxic than quercetin, in the cells. Hence, we have identified the physiological significance of the dual-regulation system by LmrA and QdoR, which is designed to regulate qdoI expression rigidly for adjusting the QdoI activity to a suitable level as necessary (Fig.…”

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confidence: 99%

“…24,25) The resultant depsides can be hydrolyzed to a pair of the respective aromatic carboxylates by an endogenous esterase with broad substrate specificity. It was reported that B. subtilis also possesses the yfiE gene, whose expression is induced by catechol and which encodes a catechol-2,3-dioxygenase capable of converting catechol into 2-hydroxymuconic semialdehyde, 43) and the ywhB gene which encodes a 4-oxalocrotonate tautomerase capable of catalyzing the interconversion of 2-hydroxymuconate and 4-oxalocrotonate.…”

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confidence: 99%

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Transcriptional response machineries of Bacillus subtilis conducive to plant growth promotion

Hirooka

2014

Bioscience, Biotechnology, and Biochemistry

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Bacillus subtilis collectively inhabits the rhizosphere, where it contributes to the promotion of plant growth, although it does not have a direct symbiotic relationship to plants as observed in the case of rhizobia between leguminous plants. As rhizobia sense the flavonoids released from their host roots through the NodD transcriptional factor, which triggers transcription of the nod genes involved in the symbiotic processes, we supposed that B. subtilis utilizes certain flavonoids as signaling molecules to perceive and adapt to the rhizospheric environment that it is in. Our approaches to identify the flavonoid-responsive transcriptional regulatory system from B. subtilis resulted in the findings that three transcriptional factors (LmrA/QdoR, YetL, and Fur) are responsive to flavonoids, with the modes of action being different from each other. We also revealed a unique regulatory system by two transcriptional factors, YcnK and CsoR, for copper homeostasis in B. subtilis. In this review, we summarize the molecular mechanisms of these regulatory systems with the relevant information and discuss their physiological significances in the mutually beneficial interaction between B. subtilis and plants, considering the possibility of their application for plant cultivation.

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“…5) Our recent study revealed that this enzyme is also able to convert other flavonols, such as fisetin, tamarixetin, and galangin, to the corresponding depsides by a similar C-ring cleavage reaction, although its catalytic activity toward fisetin is relatively low. 6) To date, several quercetin 2,3-dioxygenases have been isolated from bacteria and fungi. 7,8) Thus, they appear to be widely distributed and to play major roles in flavonol degradation in many soil microorganisms.…”

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confidence: 99%

Identification of Aromatic Residues Critical to the DNA Binding and Ligand Response of theBacillus subtilisQdoR (YxaF) Repressor Antagonized by Flavonoids

Hirooka

Fujita

2011

Bioscience, Biotechnology, and Biochemistry

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Bacillus subtilis LmrA and QdoR (formerly YxaF) are paralogous transcriptional regulators that repress their regulon comprising the lmrAB operon, the qdoR gene, and the qdoI-yxaH operon, by binding to the LmrA/QdoR boxes located in the promoter regions. Detachment of them followed by derepression of the target genes is induced by certain flavonoids. To identify the residues critical to the ligand response in QdoR, we selected eight residues based on structural information, produced eight single-mutated QdoRs in which each residue was replaced with alanine, and evaluated their capacities for DNA binding and the flavonoid response by gel retardation analysis. The three mutants, carrying the alanine substitution at Phe87, Trp131, or Phe135, showed features distinctly different from those of the wild type and from each other. We further examined the in vivo function of the mutant with alanine substitution at Trp131 by reporter assay. This largely supported the corresponding in vitro results. The in vitro and in vivo data suggest that Phe87, Trp131, and Phe135, forming a hydrophobic cluster in QdoR, play crucial roles in the DNA binding, flavonoid accommodation, and/or conformational change triggered by ligand binding.

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Excess Production ofBacillus subtilisQuercetin 2,3-Dioxygenase Affects Cell Viability in the Presence of Quercetin

Cited by 20 publications

References 29 publications

The chemistry of gut microbial metabolism of polyphenols

The chemistry of gut microbial metabolism of polyphenols

Transcriptional response machineries of Bacillus subtilis conducive to plant growth promotion

Identification of Aromatic Residues Critical to the DNA Binding and Ligand Response of theBacillus subtilisQdoR (YxaF) Repressor Antagonized by Flavonoids

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