Bacterial metabolism of 5-aminosalicylic acid. Initial ring cleavage

Nörtemann, Bernd; Knackmuss, Hans‐Joachim

doi:10.1042/bj2820675

Cited by 39 publications

(36 citation statements)

References 32 publications

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“…Another enzyme allowing substitution of one hydroxyl group with an amino group is gentisate 1,2-dioxygenase, which oxidized 5-aminosalicylic acid at a rate that is 7% of that for gentisate (12). An enzyme that cleaves 5-aminosalicylic acid as its primary substrate has also been described (32). Hence, the aromatic rings of o-aminophenols appear to be opened in a similar manner to the extradiol cleavage of catecholic substrates.…”

Section: Resultsmentioning

confidence: 98%

2-aminophenol 1,6-dioxygenase: a novel aromatic ring cleavage enzyme purified from Pseudomonas pseudoalcaligenes JS45

Lendenmann¹,

Spain²

1996

J Bacteriol

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Most bacterial pathways for the degradation of aromatic compounds involve introduction of two hydroxyl groups either ortho or para to each other. Ring fission then occurs at the bond adjacent to one of the hydroxyl groups. In contrast, 2-aminophenol is cleaved to 2-aminomuconic acid semialdehyde in the nitrobenzenedegrading strain Pseudomonas pseudoalcaligenes JS45. To examine the relationship between this enzyme and other dioxygenases, 2-aminophenol 1,6-dioxygenase has been purified by ethanol precipitation, gel filtration, and ion exchange chromatography. The molecular mass determined by gel filtration was 140,000 Da. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed two subunits of 35,000 and 39,000 Da, which suggested an ␣ 2 ␤ 2 subunit structure. Studies with inhibitors indicated that ferrous iron was the sole cofactor. The K m values for 2-aminophenol and oxygen were 4.2 and 710 M, respectively. The enzyme catalyzed the oxidation of catechol, 6-amino-m-cresol, 2-amino-m-cresol, and 2-amino-4-chlorophenol. 3-Hydroxyanthranilate, protocatechuate, gentisate, and 3-and 4-methylcatechol were not substrates. The substrate range and the subunit structure are unique among those of the known ring cleavage dioxygenases.Ring cleavage is a key reaction in microbial degradation of aromatic compounds. In aerobic bacteria, it is usually catalyzed by dioxygenases (17). Typically, substrates of ring cleavage dioxygenases feature an aromatic ring substituted with two hydroxyl groups oriented either ortho or para to each other (26). Indeed, nearly all bacterial catabolic pathways transform aromatic substrates to catechol or gentisate and their derivatives, which subsequently undergo ring cleavage (10).Recently, we reported the discovery of 2-aminophenol 1,6-dioxygenase, a new ring cleavage enzyme that catalyzes the direct conversion of 2-aminophenol to 2-aminomuconic acid semialdehyde. The enzyme is induced during the growth of Pseudomonas pseudoalcaligenes JS45 on nitrobenzene. The degradation pathway (Fig. 1A) starts with reduction of nitrobenzene to hydroxylaminobenzene followed by rearrangement to 2-aminophenol (19).Two enzymes have been reported to catalyze the ring cleavage of 2-aminophenol at very low rates. Catechol 1,2-dioxygenase from Pseudomonas arvilla C-1 catalyzes extradiol ring fission of 2-aminophenol at a rate that is 0.1% that of the intradiol cleavage of catechol (27). 2-Aminophenol was oxidized by catechol 2,3-dioxygenase from P. arvilla at a rate less than 0.01% of the rate with catechol (14, 22). These low turnover rates indicate that 2-aminophenol is not a physiological substrate of catechol 1,2-or 2,3-dioxygenase. To our knowledge, this is the first report of an enzyme that cleaves 2-aminophenol as its primary substrate.We have purified and characterized 2-aminophenol 1,6-dioxygenase from P. pseudoalcaligenes JS45 to determine how it is related to previously known ring cleavage enzymes. The tertiary structure, substrate range, and cofactor requirement were compared with that of other ri...

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Section: Resultsmentioning

confidence: 98%

2-aminophenol 1,6-dioxygenase: a novel aromatic ring cleavage enzyme purified from Pseudomonas pseudoalcaligenes JS45

Lendenmann¹,

Spain²

1996

J Bacteriol

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“…It now seems that salicylate (13,32) and a wide variety of 5-substituted salicylates (8,13,43), including 5-amino-, 5-halo-, 5-methyl-, 5-nitro-, and 5-hydroxysalicylate can be transformed by enzymes related to salicylate/gentisate 1,2-dioxygenases to open the aromatic rings. When the 5 position is replaced with a halogen or nitro group, the spontaneous lactone formation is accompanied by the elimination of HX or HNO 2 .…”

Section: Discussionmentioning

confidence: 99%

Molecular and Biochemical Characterization of the 5-Nitroanthranilic Acid Degradation Pathway in Bradyrhizobium sp. Strain JS329

Spain

2011

J Bacteriol

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Biodegradation pathways of synthetic nitroaromatic compounds and anilines are well documented, but little is known about those of nitroanilines. We previously reported that the initial step in 5-nitroanthranilic acid (5NAA) degradation by Bradyrhizobium sp. strain JS329 is a hydrolytic deamination to form 5-nitrosalicylic acid (5NSA), followed by ring fission catalyzed by 5NSA dioxygenase. The mechanism of release of the nitro group was unknown. In this study, we subcloned, sequenced, and expressed the genes encoding 5NAA deaminase (5NAA aminohydrolase, NaaA), 5NSA dioxygenase (NaaB) and lactonase (NaaC), the key genes responsible for 5NAA degradation. Sequence analysis and enzyme characterization revealed that NaaA is a hydrolytic metalloenzyme with a narrow substrate range. The nitro group is spontaneously eliminated as nitrite concomitant with the formation of a lactone from the ring fission product of 5NSA dioxygenation. The elimination of the nitro group during lactone formation is a previously unreported mechanism for denitration of nitro aliphatic compounds.

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“…The oxidation of 1-hydroxy-2-naphthoate was determined spectrophotometrically at 300 nm (molar reaction coefficient [ε 300 ] ϭ 11.5 mM Ϫ1 cm Ϫ1 ) as previously described by Iwabuchi and Harayama (15 (37,41).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast to the degradation of (substituted) naphthalenesulfonic acids to the corresponding salicylates, the productive metabolism of (substituted) salicylates requires rather different metabolic pathways. Thus, salicylate is usually converted by a salicylate 1-monooxygenase to catechol, 3-hydroxysalicylate (2,3-dihyroxybenzoate) is directly oxidized by an extradiol ring fission reaction to a nonaromatic product, 4-hydroxysalicylate (2,4-dihydroxybenzoate) is converted by a monooxygenase to the ring fission substrate 1,2,4-trihydroxybenzene, and gentisate (5-hydroxysalicylate) and 5-aminosalicylate are substrates for ring fission dioxygenases (2,36,37,41,42).…”

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confidence: 99%

Direct Ring Fission of Salicylate by a Salicylate 1,2-Dioxygenase Activity from Pseudaminobacter salicylatoxidans

et al. 2001

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In cell extracts of Pseudaminobacter salicylatoxidans strain BN12, an enzymatic activity was detected which converted salicylate in an oxygen-dependent but NAD(P)H-independent reaction to a product with an absorbance maximum at 283 nm. This metabolite was isolated, purified, and identified by mass spectrometry and 1 H and 13 C nuclear magnetic resonance spectroscopy as 2-oxohepta-3,5-dienedioic acid. This metabolite could be formed only by direct ring fission of salicylate by a 1,2-dioxygenase reaction. Cell extracts from P. salicylatoxidans also oxidized 5-aminosalicylate, 3-, 4-, and 5-chlorosalicylate, 3-, 4-, and 5-methylsalicylate, 3-and 5-hydroxysalicylate (gentisate), and 1-hydroxy-2-naphthoate. The dioxygenase was purified and shown to consist of four identical subunits with a molecular weight of about 45,000. The purified enzyme showed higher catalytic constants with gentisate or 1-hydroxy-2-naphthoate than with salicylate. It was therefore concluded that P. salicylatoxidans synthesized a gentisate 1,2-dioxygenase with an extraordinary substrate range, which also allowed the oxidation of salicylate.Naphthalenesulfonic acids are produced on a large scale as industrial detergents, dispersive materials, and intermediates for the production of azo dyes (34). Some pure and mixed bacterial cultures which grow with naphthalene-1-sulfonic acid, naphthalene-2-sulfonic acid (2NS), 2-aminonaphthalene-1-sulfonic acid, 6-aminonaphthalene-2-sulfonic acid (6A2NS), or naphthalenedisulfonic acids as the sole source of carbon and energy have been isolated. The initial reaction in the microbial degradation of (substituted) naphthalenesulfonic acids is catalyzed by desulfonating dioxygenases, which catalyze the formation of (substituted) 1,2-dihydroxynaphthalene(s) and the release of sulfite (4, 5, 26-30, 32, 44). Thus, the degradative pathway for naphthalenesulfonic acids converges at the level of 1,2-dihydroxynaphthalene (1,2-DHN) with the well-known pathway for the degradation of naphthalene (Fig. 1). The reactions which are catalyzed by the "upper" naphthalenesulfonic acid pathway result in the formation of (substituted) salicylate(s). For Sphingomonas xenophaga BN6, it was found that the enzymes participating in the upper naphthalenesulfonic acid pathway convert a wide range of substituted substrates and that therefore a single set of enzymes is sufficient for the conversion of various substituted naphthalenesulfonic acids (19-21, 26, 27, 35). In contrast to the degradation of (substituted) naphthalenesulfonic acids to the corresponding salicylates, the productive metabolism of (substituted) salicylates requires rather different metabolic pathways. Thus, salicylate is usually converted by a salicylate 1-monooxygenase to catechol, 3-hydroxysalicylate (2,3-dihyroxybenzoate) is directly oxidized by an extradiol ring fission reaction to a nonaromatic product, 4-hydroxysalicylate (2,4-dihydroxybenzoate) is converted by a monooxygenase to the ring fission substrate 1,2,4-trihydroxybenzene, and gentisate (5-hydroxysalicylate...

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Bacterial metabolism of 5-aminosalicylic acid. Initial ring cleavage

Cited by 39 publications

References 32 publications

2-aminophenol 1,6-dioxygenase: a novel aromatic ring cleavage enzyme purified from Pseudomonas pseudoalcaligenes JS45

2-aminophenol 1,6-dioxygenase: a novel aromatic ring cleavage enzyme purified from Pseudomonas pseudoalcaligenes JS45

Molecular and Biochemical Characterization of the 5-Nitroanthranilic Acid Degradation Pathway in Bradyrhizobium sp. Strain JS329

Direct Ring Fission of Salicylate by a Salicylate 1,2-Dioxygenase Activity from Pseudaminobacter salicylatoxidans

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