Molecular Analysis of the Gene Encoding F
            <sub>420</sub>
            -Dependent Glucose-6-Phosphate Dehydrogenase from
            <i>Mycobacterium smegmatis</i>

Purwantini, Endang; Daniels, Lacy

doi:10.1128/jb.180.8.2212-2219.1998

Cited by 46 publications

(18 citation statements)

References 65 publications

(62 reference statements)

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“…To test whether FGD catalysed aflatoxin degradation, it was heterologously expressed in and purified from Escherichia coli. As expected, FGD could catalyse the reduction of F420 to F420H2 in the presence of glucose 6-phosphate (Purwantini and Daniels, 1998;Bashiri et al, 2008). However, neither FGD in the presence of F420/ F420H2, nor F420H2 in isolation, were able to catalyse aflatoxin breakdown at detectable levels.…”

Section: Aflatoxin Degradation Is Cofactor F420-dependentsupporting

confidence: 65%

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Taylor

Jackson

Tattersall

et al. 2010

Molecular Microbiology

144

197

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Aflatoxins are polyaromatic mycotoxins that contaminate a range of food crops as a result of fungal growth and contribute to serious health problems in the developing world because of their toxicity and mutagenicity. Although relatively resistant to biotic degradation, aflatoxins can be metabolized by certain species of Actinomycetales. However, the enzymatic basis for their breakdown has not been reported until now. We have identified nine Mycobacterium smegmatis enzymes that utilize the deazaflavin cofactor F420H2 to catalyse the reduction of the α,β-unsaturated ester moiety of aflatoxins, activating the molecules for spontaneous hydrolysis and detoxification. These enzymes belong to two previously uncharacterized F420H2 dependent reductase (FDR-A and -B) families that are distantly related to the flavin mononucleotide (FMN) dependent pyridoxamine 5′-phosphate oxidases (PNPOxs). We have solved crystal structures of an enzyme from each FDR family and show that they, like the PNPOxs, adopt a split barrel protein fold, although the FDRs also possess an extended and highly charged F420H2 binding groove. A general role for these enzymes in xenobiotic metabolism is discussed, including the observation that the nitro-reductase Rv3547 from Mycobacterium tuberculosis that is responsible for the activation of bicyclic nitroimidazole prodrugs belongs to the FDR-A family.

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Section: Aflatoxin Degradation Is Cofactor F420-dependentsupporting

confidence: 65%

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Taylor

Jackson

Tattersall

et al. 2010

Molecular Microbiology

144

197

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“…Of these, the Rv0132c possible Lpp has been annotated as a putative F 420 -dependent glucose-6-phosphate dehydrogenase due to its homology with an M. smegmatis enzyme [67]. However, the most significant homology resides in the N-terminal domain which is likely to interact with the F 420 coenzyme [67] whereas their C-terminal regions show much lower homology. Thus it would seem prudent to consider this enzyme a putative F 420 -dependent oxidoreducase until its substrate specificity has been directly demonstrated.…”

Section: Other Enzymes and Metabolic Activitiesmentioning

confidence: 99%

Lipoproteins ofMycobacterium tuberculosis: an abundant and functionally diverse class of cell envelope components

2004

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Mycobacterium tuberculosis remains the predominant bacterial scourge of mankind. Understanding of its biology and pathogenicity has been greatly advanced by the determination of whole genome sequences for this organism. Bacterial lipoproteins are a functionally diverse class of membrane-anchored proteins. The signal peptides of these proteins direct their export and post-translational lipid modification. These signal peptides are amenable to bioinformatic analysis, allowing the lipoproteins encoded in whole genomes to be catalogued. This review applies bioinformatic methods to the identification and functional characterisation of the lipoproteins encoded in the M. tuberculosis genomes. Ninety nine putative lipoproteins were identified and so this family of proteins represents ca. 2.5% of the M. tuberculosis predicted proteome. Thus, lipoproteins represent an important class of cell envelope proteins that may contribute to the virulence of this major pathogen.

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“…In Mycobacterium smegmatis, F 420 is important for decolorization of malachite green, and mutants not making F 420 are more sensitive to superoxide-mediated oxidative stress (18). Although Fgd shows no significant homology with NADPdependent glucose-6-phosphate dehydrogenase (G6PDH) (19), both catalyze similar electron transfer reactions and require glucose 6-phosphate (G6P) as the source of electrons to make reduced coenzymes F 420 H 2 and NADPH, respectively. Glucose 6-phosphate, derived from glucose through the glycolytic enzymes hexokinase or glucokinase and through gluconeogenesis, generates reducing power via the pentose phosphate pathway.…”

mentioning

confidence: 99%

Glucose 6-Phosphate Accumulation in Mycobacteria

Hasan¹,

Rahman²,

Jaques³

et al. 2010

Journal of Biological Chemistry

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Glucose 6-phosphate (G6P) is a metabolic intermediate with many possible cellular fates. In mycobacteria, G6P is a substrate for an enzyme, F 420 -dependent glucose-6-phosphate dehydrogenase (Fgd), found in few bacterial genera. Intracellular G6P levels in six Mycobacterium sp. were remarkably higher (ϳ17-130-fold) than Escherichia coli and Bacillus megaterium. The high G6P level in Mycobacterium smegmatis may result from 10 -25-fold higher activity of the gluconeogenic enzyme fructose-1,6-bisphosphatase when grown on glucose, glycerol, or acetate compared with B. megaterium and E. coli. In M. smegmatis this coincided with up-regulation of the first gluconeogenic enzyme, phosphoenolpyruvate carboxykinase, when acetate was the carbon source, suggesting a cellular program for maintaining high G6P levels. G6P was depleted in cells under oxidative stress induced by redox cycling agents plumbagin and menadione, whereas an fgd mutant of M. smegmatis used G6P less well under such conditions. The fgd mutant was more sensitive to these agents and, in contrast to wild type, was defective in its ability to reduce extracellular plumbagin and menadione. These data suggest that intracellular G6P in mycobacteria serves as a source of reducing power and, with the mycobacteriaspecific Fgd-F 420 system, plays a protective role against oxidative stress.

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Molecular Analysis of the Gene Encoding F ₄₂₀ -Dependent Glucose-6-Phosphate Dehydrogenase from Mycobacterium smegmatis

Cited by 46 publications

References 65 publications

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Lipoproteins ofMycobacterium tuberculosis: an abundant and functionally diverse class of cell envelope components

Glucose 6-Phosphate Accumulation in Mycobacteria

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Molecular Analysis of the Gene Encoding F 420 -Dependent Glucose-6-Phosphate Dehydrogenase from Mycobacterium smegmatis

Cited by 46 publications

References 65 publications

Identification and characterization of two families of F420H2‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Identification and characterization of two families of F420H2‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Lipoproteins ofMycobacterium tuberculosis: an abundant and functionally diverse class of cell envelope components

Glucose 6-Phosphate Accumulation in Mycobacteria

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Product

Resources

About

Molecular Analysis of the Gene Encoding F ₄₂₀ -Dependent Glucose-6-Phosphate Dehydrogenase from Mycobacterium smegmatis

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation

Identification and characterization of two families of F₄₂₀H₂‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation