Degradation of rutin by <i>Aspergillus flavus</i>. Studies on specificity, inhibition, and possible reaction mechanism of quercetinase

Oka, Toshihiko; Simpson, F. J.; Krishnamurty, H. G.

doi:10.1139/m72-076

Cited by 87 publications

(102 citation statements)

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“…The geometry displayed by DDC and KOJ appears to be generally achievable by a wide number of small molecules with chelating ability. Among those that have already been proven to inhibit 2,3QD activity (9,30) ,c and 4). In 2,3QD‚DDC, the large DDC sulfur atom at a shorter distance from the Cu ion precludes ligation of the Glu73 side chain to the metal.…”

Section: Discussionmentioning

confidence: 99%

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

2002

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Functional analysis of the copper-dependent quercetin 2,3-dioxygenase. 1. Ligand-induced coordination changes probed by X-ray crystallography Steiner, Roberto A.; Kooter, Ingeborg M.; Dijkstra, Bauke W. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2002Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Steiner, R. A., Kooter, I. M., & Dijkstra, B. W. (2002). Functional analysis of the copper-dependent quercetin 2,3-dioxygenase. 1. Ligand-induced coordination changes probed by X-ray crystallography: Inhibition, ordering effect, and mechanistic insights. Biochemistry, 41(25), 7955-7962. DOI: 10.1021/bi0159736 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. ReceiVed NoVember 26, 2001; ReVised Manuscript ReceiVed May 7, 2002 ABSTRACT: The crystal structures of the copper-dependent Aspergillus japonicus quercetin 2,3-dioxygenase (2,3QD) complexed with the inhibitors diethyldithiocarbamate (DDC) and kojic acid (KOJ) are reported at 1.70 and 2.15 Å resolution, respectively. Both inhibitors asymmetrically chelate the metal center and assume a common orientation in the active site cleft. Their molecular plane blocks access to the inner portion of the cavity which is lined by the side chains of residues Met51, Thr53, Phe75, Phe114, and Met123 and which is believed to bind the flavonol B-ring of the natural substrate. The binding of the inhibitors brings order into the mixed coordination observed in the native enzyme. DDC and KOJ induce a single conformation of the Glu73 side chain, although in different ways. In the presence of DDC, Glu73 is detached from the copper ion with its carboxylate moiety pointing away from the active site cavity. In contrast, when KOJ is bound, Glu73 ligates the Cu ion through its O 1 atom with a monodentate geometry. Compared to the native coordinating conformation, this conformation is approximately 90°rotated about the 3 angle. This latter Glu73 conformation is compatible with the presence of a bound substrate.Dioxygenases are enzymes that catalyze the incorporation of both atoms of molecular oxygen into organic substrates. They take part in the metabolism of biomolecules as different as amino acids, lipids, nucleic acids, and even carbohydrates (1...

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Section: Discussionmentioning

confidence: 99%

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

2002

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“…The DMSO content of the soaking solution was 10% (vol͞vol). At this concentration, DMSO does not inhibit the enzyme (9,11). All oxygen-free crystal manipulations were carried out in an anaerobic chamber (Belle Technology, Portesham, Dorset, U.K.) at an O 2 pressure lower than 1-2 ppm.…”

Section: Methodsmentioning

confidence: 99%

“…1). The general lines of a possible mechanism for the enzymatic process have been suggested by the early biochemical work on Aspergillus flavus 2,3QD (11) and by model studies (12)(13)(14). To overcome the singlet-triplet spin barrier, the reaction has been proposed to proceed through a Cu ϩ -flavonoxy radical formed from tautomerization of the Cu 2ϩ -flavonolate adduct.…”

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confidence: 99%

Anaerobic enzyme⋅substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase

Steiner

Kalk

Dijkstra

2002

Proc. Natl. Acad. Sci. U.S.A.

172

180

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Quercetin 2,3-dioxygenase (2,3QD) is the only firmly established copper dioxygenase known so far. Depending solely on a mononuclear Cu center, it catalyzes the breakage of the O-heterocycle of flavonols, producing more easily degradable phenolic carboxylic acid ester derivatives. In the enzymatic process, two COC bonds are broken and concomitantly carbon monoxide is released. The x-ray structures of Aspergillus japonicus 2,3QD anaerobically complexed with the substrate kaempferol and the natural substrate quercetin have been determined at 1.90-and 1.75-Å resolution, respectively. Flavonols coordinate to the copper ion as monodentate ligands through their 3OH group. They occupy a shallow and overall hydrophobic cavity proximal to the metal center. As a result of a van der Waals contact between the most outward flavonol A-ring and Pro 164 , a flexible loop in front of the active site becomes partly ordered. Interestingly, flavonols bound to 2,3QD are bent at the C2 atom, which is pyramidalized. The increased local sp 3 character at this atom may stabilize a carbon-centered radical activated for dioxygen attack. I n several aerobic metabolic pathways, O 2 is incorporated into organic compounds through monooxygenase-or dioxygenasecatalyzed reactions (1). For instance, oxygenation is often used to make lipids and particularly aromatic molecules amenable to further biochemical transformations. However, owing to its triplet ground state, O 2 cannot directly react with singlet ground state substrates to produce singlet state products because that would imply a violation of the conservation of the total angular momentum (2). Some form of activation, that is, some way to overcome the spin forbiddenness of the process, is therefore required to make dioxygen react with organic molecules. Often, metal cofactors are used for this purpose, with iron almost invariably being the element of choice for dioxygenases (3). Detailed crystallographic and spectroscopic studies have elucidated how the mononuclear non-heme iron center in these enzymes is exploited to accomplish catalysis (for reviews, see refs. 4 and 5). It seemed that the extradiol-type dioxygenases use an Fe 2ϩ ion to directly ligate and activate O 2 , whereas the intradiol-type enzymes employ Fe 3ϩ to activate the substrate before dioxygen attack.Quercetin 2,3-dioxygenase (2,3QD) belongs to the cupin superfamily (6, 7) and is the only dioxygenase unambiguously known to rely on a mononuclear copper center for activity (8-10). It is a type 2 copper-dependent enzyme expressed by Aspergillus species when grown on complex aromatic compounds, such as rutin or quercetin. 2,3QD catalyzes the cleavage of the O-heteroaromatic ring of flavonols, yielding the corresponding depside (phenolic carboxylic acid ester) and carbon monoxide (Fig. 1). The general lines of a possible mechanism for the enzymatic process have been suggested by the early biochemical work on Aspergillus flavus 2,3QD (11) and by model studies (12)(13)(14). To overcome the singlet-triplet spin barrier, the reacti...

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“…Some of these studies established degradation pathways for flavonoids such as rutin 8 ) and phellaamurin. 4 } On the other hand, there has been few reports.…”

Section: Received September 19 1985mentioning

confidence: 99%

Formation of 2,4,6-Trihydroxycarboxylic Acid and 2-Protocatechuoylphloroglucinolcarboxylic Acid from Rutin by Bacteria

Omori

Shiozawa

Sekiya

et al. 1986

Agricultural and Biological Chemistry

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Degradation of rutin by Aspergillus flavus. Studies on specificity, inhibition, and possible reaction mechanism of quercetinase

Cited by 87 publications

References 0 publications

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

Anaerobic enzyme⋅substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase

Formation of 2,4,6-Trihydroxycarboxylic Acid and 2-Protocatechuoylphloroglucinolcarboxylic Acid from Rutin by Bacteria

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