Occurrence of molybdenum in the nicotinic acid hydroxylase from Clostridium barkeri

Dilworth, Gregory L.

doi:10.1016/0003-9861(83)90176-5

Cited by 39 publications

(14 citation statements)

References 16 publications

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“…Close inspection of the data (23) indicates that the enzyme exhibits a small peak at 411 nm indicative of a cytochrome, which also might have been lost. Formation of the hydroxylated intermediate seems to be quite similar to the hydroxylation of N-heterocyclic compounds such as purines (4), nicotine (13), nicotinic acid (11,34), or picolinic acid (44), as noted before (23). A relationship of the two reactions is indicated by the observed unspecificity of XDH for 2-furoylCoA, as observed in our strain P. putida Ful (24).…”

Section: Discussionsupporting

confidence: 76%

“…According to our study, two different types of XDH have evolved. In both types, XDH is a molybdoprotein of about 300,000 Da in its native size (Table 2) and shows a broader substrate spectrum than the proteins, such as nicotinate dehydrogenase (11) or FCoADH (24), that might have derived from it. Both types contain certain enzymes that are active as 150,000 Da form.…”

Section: Discussionmentioning

confidence: 99%

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Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonas putida Fu1: two molybdenum-containing dehydrogenases of novel structural composition

Koenig

Andreesen

1990

J Bacteriol

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The constitutive xanthine dehydrogenase and the inducible 2-furoyl-coenzyme A (CoA) dehydrogenase could be labeled with ['85W]tungstate. This labeling was used as a reporter to purify both labile proteins. The radioactivity cochromatographed predominantly with the residual enzymatic activity of both enzymes during the first purification steps. Both radioactive proteins were separated and purified to homogeneity. Antibodies raised against the larger protein also exhibited cross-reactivity toward the second smaller protein and removed xanthine dehydrogenase and 2-furoyl-CoA dehydrogenase activity up to 80 and 60% from the supernatant of cell extracts, respectively. With use of cell extract, Western immunoblots showed only two bands which correlated exactly with the activity stains for both enzymes after native polyacrylamide gel electrophoresis. Molybdate was absolutely required for incorporation of '85W, formation of cross-reacting material, and enzymatic activity. The latter parameters showed a perfect correlation. This evidence proves that the radioactive proteins were actually xanthine dehydrogenase and 2-furoyl-CoA dehydrogenase. The apparent molecular weight of the native xanthine dehydrogenase was about 300,000, and that of 2-furoyl-CoA dehydrogenase was 150,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of both enzymes revealed two protein bands corresponding to molecular weights of 55,000 and 25,000. The xanthine dehydrogenase contained at least 1.6 mol of molybdenum, 0.9 ml of cytochrome b, 5.8 mol of iron, and 2.4 mol of labile sulfur per mol of enzyme. The composition of the 2-furoyl-CoA dehydrogenase seemed to be similar, although the stoichiometry was not determined. The oxidation of furfuryl alcohol to furfural and further to 2-furoic acid by Pseudomonas putida Ful was catalyzed by two different dehydrogenases.Pseudomonas putida Ful was isolated from an enrichment culture with 2-furoic acid as the sole source of carbon and energy (24). The formation of 2-furoyl-coenzyme A (CoA) is the first reaction step in 2-furoic acid degradation. The second enzymatic step is catalyzed by a dehydrogenase that introduces a hydroxyl group to form 5-hydroxy-2-furoylCoA (23,24,49,50). Other substrates for P. putida Ful were furfuryl alcohol and furfural, which were degraded via 2-furoic acid and 2-furoyl-CoA (Fig.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonas putida Fu1: two molybdenum-containing dehydrogenases of novel structural composition

Koenig

Andreesen

1990

J Bacteriol

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“…1). Three enzymes have been shown to require selenium in a labile form: xanthine dehydrogenase (XDH) from Clostridium acidurici (15,58,59), Clostridium cylindrosporum (12,59), Clostridium purinilyticum (16,49,50), and Eubacterium barkeri (43); nicotinic acid hydroxylase (NAH) from E. barkeri (13,14,17,18,25,38,57); and purine hydroxylase (PH) from C. purinilyticum (49,50). The strictly anaerobic bacteria which express these labile selenoenzymes were originally isolated in enrichment cultures using uric acid (C. acidurici, C. cylindrosporum), nicotinic acid (E. barkeri), or adenine (C. purinilyticum) as a primary source of carbon, nitrogen, and energy.…”

mentioning

confidence: 99%

A Selenium-Dependent Xanthine Dehydrogenase Triggers Biofilm Proliferation inEnterococcus faecalisthrough Oxidant Production

et al. 2011

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Selenium has been shown to be present as a labile cofactor in a small class of molybdenum hydroxylase enzymes in several species of clostridia that specialize in the fermentation of purines and pyrimidines. This labile cofactor is poorly understood, yet recent bioinformatic studies have suggested that Enterococcus faecalis could serve as a model system to better understand the way in which this enzyme cofactor is built and the role of these metalloenzymes in the physiology of the organism. An mRNA that encodes a predicted seleniumdependent molybdenum hydroxylase (SDMH) has also been shown to be specifically increased during the transition from planktonic growth to biofilm growth. Based on these studies, we examined whether this organism produces an SDMH and probed whether selenoproteins may play a role in biofilm physiology. We observed a substantial increase in biofilm density upon the addition of uric acid to cells grown in a defined culture medium, but only when molybdate (Mo) and selenite (Se) were also added. We also observed a significant increase in biofilm density in cells cultured in tryptic soy broth with 1% glucose (TSBG) when selenite was added. In-frame deletion of selD, which encodes selenophosphate synthetase, also blocked biofilm formation that occurred upon addition of selenium. Moreover, mutation in the gene encoding the molybdoenzyme (xdh) prevented the induction of biofilm proliferation upon supplementation with selenium. Tungstate or auranofin addition also blocked this enhanced biofilm density, likely through inhibition of molybdenum or selenium cofactor synthesis. A large protein complex labeled with 75 Se is present in higher concentrations in biofilms than in planktonic cells, and the same complex is formed in TSBG. Xanthine dehydrogenase activity correlates with the presence of this labile selenoprotein complex and is absent in a selD or an xdh mutant. Enhanced biofilm density correlates strongly with higher levels of extracellular peroxide, which is produced upon the addition of selenite to TSBG. Peroxide levels are not increased in either the selD or the xdh mutant upon addition of selenite. Extracellular superoxide production, a phenomenon well established to be linked to clinical isolates, is abolished in both mutant strains. Taken together, these data provide evidence that an SDMH is involved in biofilm formation in Enterococcus faecalis, contributing to oxidant production either directly or alternatively through its involvement in redox-dependent processes linked to oxidant production.

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“…A notable exception to the concept of a universal molybdenum cofactor was the demonstration that nitrogenase in fact contains a unique iron-molybdenum cofactor that is not interchangeable with that in other molybdoenzymes (3). The identification of a pterin as the organic component of the molybdenum cofactor, first in sulfite oxidase, xanthine oxidase, and nitrate reductase (4), and later in a host of other molybdoenzymes (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), lent further credence to the idea of a common molybdenum cofactor. However, the organic component of the molybdenum cofactor, termed molybdopterin, is extremely unstable when released from its protein environment and has never been structurally characterized in its native state.…”

mentioning

confidence: 99%

Molybdopterin guanine dinucleotide: a modified form of molybdopterin identified in the molybdenum cofactor of dimethyl sulfoxide reductase from Rhodobacter sphaeroides forma specialis denitrificans.

Johnson

Bastian

Rajagopalan

1990

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

139

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The nature of molybdenum cofactor in the bacterial enzyme dimethyl sulfoxide reductase has been investigated by application of alkylation conditions that convert the molybdenum cofactor in chicken liver sulfite oxidase and milk xanthine oxidase to the stable, well-characterized derivative [di(carboxamidomethyl)Jmolybdopterin. The alkylated pterin obtained from dimethyl sulfoxide reductase was shown to be a modified form of alkylated molybdopterin with increased absorption in the 250-nm region of the spectrum and altered chromatographic behavior. The complex alkylated pterin was resolved into two components by treatment with nucleotide pyrophosphatase. These were identified as di(carboxamidomethyl)molybdopterin and GMP by their absorption spectra, coelution with standard compounds, and by further degradation by alkaline phosphatase to dephospho [di(carboxamidomethyl)]molybdopterin and guanosine. The GMP moiety was sensitive to periodate, identifying it as the 5' isomer. Chemical analysis of the intact alkylated pterin showed the presence of two phosphate residues per pterin. These results established that the pterin isolated from dimethyl sulfoxide reductase contains the phosphoric anhydride of molybdopterin and 5'-GMP, which is designated molybdopterin guanine dinucleotide.The suggestion that all molybdoenzymes contain a common molybdenum cofactor consisting of a low molecular weight organic component complexed to the metal was first put forward in 1964 upon the identification of pleiotropic mutants of Aspergillus nidulans that lacked the activities of nitrate reductase and xanthine dehydrogenase (1). In 1971 it was demonstrated that acidified extracts of molybdoenzymes from diverse sources could reconstitute nitrate reductase activity in extracts of a pleiotropic mutant of Neurospora crassa deficient in functional molybdenum cofactor (2). A notable exception to the concept of a universal molybdenum cofactor was the demonstration that nitrogenase in fact contains a unique iron-molybdenum cofactor that is not interchangeable with that in other molybdoenzymes (3). The identification of a pterin as the organic component of the molybdenum cofactor, first in sulfite oxidase, xanthine oxidase, and nitrate reductase (4), and later in a host of other molybdoenzymes (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), lent further credence to the idea of a common molybdenum cofactor. However, the organic component of the molybdenum cofactor, termed molybdopterin, is extremely unstable when released from its protein environment and has never been structurally characterized in its native state. Instead its structure was deduced from analysis of a number of stable degradation products-form A, form B, and urothione (18, 19)-and was confirmed by specific derivatization of the reactive vicinal sulfhydryl groups producing the dicarboxamidomethyl derivative [di-(carboxamidomethyl)]molybdopterin (camMPT) shown in Fig. 1 (20). Generation of camMPT represented a significant advance in the understanding of molybdopterin chemistr...

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Occurrence of molybdenum in the nicotinic acid hydroxylase from Clostridium barkeri

Cited by 39 publications

References 16 publications

Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonas putida Fu1: two molybdenum-containing dehydrogenases of novel structural composition

Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonas putida Fu1: two molybdenum-containing dehydrogenases of novel structural composition

A Selenium-Dependent Xanthine Dehydrogenase Triggers Biofilm Proliferation inEnterococcus faecalisthrough Oxidant Production

Molybdopterin guanine dinucleotide: a modified form of molybdopterin identified in the molybdenum cofactor of dimethyl sulfoxide reductase from Rhodobacter sphaeroides forma specialis denitrificans.

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