Enzymatic Characterization of 5-Methylthioribose 1-Phosphate Isomerase from<i>Bacillus subtilis</i>

Saito, Yohtaro; Ashida, Hiroshi; Kojima, Chojiro; Tamura, Haruka; Matsumura, Hideki; Yokota, Akiho

doi:10.1271/bbb.70209

Cited by 20 publications

(31 citation statements)

References 24 publications

(31 reference statements)

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“…The 5-deoxyribose 1-phosphate (5-dRP) product could be incorporated into the deoxyhexoses required for aromatic amino acid biosynthesis without coming from the traditional pentose pathway shunt. This could involve an isomerase (MJ0454 gene product) that is annotated to use the 5=-methylthio derivative of 5-dRP to produce 5-deoxyribulose-1-phosphate typically involved in the methionine salvage pathway (28,29). This compound could be further metabolized by several yet to be identified enzymes to produce 6-deoxy-5-ketofructose, the required precursor for aromatic amino acid (Fig.…”

Section: Figmentioning

confidence: 99%

Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Miller¹,

O’Brien²,

Xu³

et al. 2013

Journal of Bacteriology

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We characterize here the MJ1541 gene product from Methanocaldococcus jannaschii, an enzyme that was annotated as a 5=-methylthioadenosine/S-adenosylhomocysteine deaminase (EC 3.5.4.31/3.5.4.28). The MJ1541 gene product catalyzes the conversion of 5=-deoxyadenosine to 5=-deoxyinosine as its major product but will also deaminate 5=-methylthioadenosine, S-adenosylhomocysteine, and adenosine to a small extent. On the basis of these findings, we are naming this new enzyme 5=-deoxyadenosine deaminase (DadD). The K m for 5=-deoxyadenosine was found to be 14.0 ؎ 1.2 M with a k cat /K m of 9.1 ؋ 10 9 M ؊1 s ؊1 . Radical S-adenosylmethionine (SAM) enzymes account for nearly 2% of the M. jannaschii genome, where the major SAM derived products is 5=-deoxyadenosine. Since 5=-dA has been demonstrated to be an inhibitor of radical SAM enzymes; a pathway for removing this product must be present. We propose here that DadD is involved in the recycling of 5=-deoxyadenosine, whereupon the 5=-deoxyribose moiety of 5=-deoxyinosine is further metabolized to deoxyhexoses used for the biosynthesis of aromatic amino acids in methanogens.

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Section: Figmentioning

confidence: 99%

Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Miller¹,

O’Brien²,

Xu³

et al. 2013

Journal of Bacteriology

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“…20) MtnA was not removed the before measurement of MtnB activity. The remaining MtnA in the assay mixture did not affect MtnB activity, since the MtnB activity was calculated using an absorbance change at 280 nm for the initial 20 s. The slope of the increase in absorbance at 280 nm for the initial 20 s in each measurement was linear.…”

Section: )mentioning

confidence: 99%

Enzymatic Characterization of 5-Methylthioribulose-1-phosphate Dehydratase of the Methionine Salvage Pathway inBacillus subtilis

Ashida

Saito

Kojima

et al. 2008

Bioscience, Biotechnology, and Biochemistry

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“…MTR1P isomerase functions in the methionine salvage pathway and catalyzes a similar reaction, the isomerization of MTR1P, an aldopentose with a phosphorylated 1-hydroxy group, to 5-methylthioribulose 1-phosphate (2,26). Enzymatic (22) and structural (5,29) examinations have been carried out on the enzymes from Bacillus subtilis and Saccharomyces cerevisiae.…”

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Enzymatic Characterization of AMP Phosphorylase and Ribose-1,5-Bisphosphate Isomerase Functioning in an Archaeal AMP Metabolic Pathway

et al. 2012

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dAMP phosphorylase (AMPpase), ribose-1,5-bisphosphate (R15P) isomerase, and type III ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) have been proposed to constitute a novel pathway involved in AMP metabolism in the Archaea. Here we performed a biochemical examination of AMPpase and R15P isomerase from Thermococcus kodakarensis. R15P isomerase was specific for the ␣-anomer of R15P and did not recognize other sugar compounds. We observed that activity was extremely low with the substrate R15P alone but was dramatically activated in the presence of AMP. Using AMP-activated R15P isomerase, we reevaluated the substrate specificity of AMPpase. AMPpase exhibited phosphorylase activity toward CMP and UMP in addition to AMP. The [S]-v plot (plot of velocity versus substrate concentration) of the enzyme toward AMP was sigmoidal, with an increase in activity observed at concentrations higher than approximately 3 mM. The behavior of the two enzymes toward AMP indicates that the pathway is intrinsically designed to prevent excess degradation of intracellular AMP. We further examined the formation of 3-phosphoglycerate from AMP, CMP, and UMP in T. kodakarensis cell extracts. 3-Phosphoglycerate generation was observed from AMP alone, and from CMP or UMP in the presence of dAMP, which also activates R15P isomerase. 3-Phosphoglycerate was not formed when 2-carboxyarabinitol 1,5-bisphosphate, a Rubisco inhibitor, was added. The results strongly suggest that these enzymes are actually involved in the conversion of nucleoside monophosphates to 3-phosphoglycerate in T. kodakarensis.A rchaea comprise the third domain of life and exhibit unique metabolic features that are not found in bacteria and eukaryotes. The metabolic enzymes and pathways utilized for glycolysis and pentose biosynthesis in many archaea differ from the classical Embden-Meyerhof (EM)/Entner-Doudoroff (ED) pathways (24,27,33,35) and the pentose phosphate pathway (11,19,28), respectively. A previous study of the hyperthermophilic archaeon Thermococcus kodakarensis KOD1 (3, 9) suggested the presence of a novel pathway involved in nucleic acid metabolism (25). The pathway consists of a type III ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and two novel enzymes, AMP phosphorylase (AMPpase) and ribose-1,5-bisphosphate (R15P) isomerase. In the first reaction of this pathway, catalyzed by AMPpase, the adenine base of AMP is released and is replaced by a phosphate group to generate R15P. In the following R15P isomerase reaction, R15P is converted to ribulose 1,5-bisphosphate (RuBP). In the final reaction, Rubisco catalyzes the conversion of RuBP, CO 2 , and H 2 O to 2 molecules of 3-phosphoglycerate (3-PGA), which is an intermediate of central sugar metabolism. Genome sequences indicate that this pathway is distributed broadly among the Archaea, including all members of the Thermococcales, Archaeoglobales, Methanomicrobiales, and Methanosarcinales. The pathway is also found in several members of the Halobacteriales, Methanococcales, Desulfurococcales...

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Enzymatic Characterization of 5-Methylthioribose 1-Phosphate Isomerase fromBacillus subtilis

Cited by 20 publications

References 24 publications

Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Enzymatic Characterization of 5-Methylthioribulose-1-phosphate Dehydratase of the Methionine Salvage Pathway inBacillus subtilis

Enzymatic Characterization of AMP Phosphorylase and Ribose-1,5-Bisphosphate Isomerase Functioning in an Archaeal AMP Metabolic Pathway

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