scholarly journals The Ribulose Monophosphate Pathway Substitutes for the Missing Pentose Phosphate Pathway in the Archaeon Thermococcus kodakaraensis

2006 ◽  
Vol 188 (13) ◽  
pp. 4698-4704 ◽  
Author(s):  
Izumi Orita ◽  
Takaaki Sato ◽  
Hiroya Yurimoto ◽  
Nobuo Kato ◽  
Haruyuki Atomi ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Deletion Mutant ◽  
Minimal Medium ◽  
Catalytic Properties ◽  
Pentose Phosphate ◽  
Genetic Approach ◽  
Reading Frame ◽  
Ribulose Monophosphate Pathway ◽  
Pentose Phosphate Pathways ◽  
Genome Analyses

ABSTRACT The ribulose monophosphate (RuMP) pathway, involving 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI), is now recognized as a widespread prokaryotic pathway for formaldehyde fixation and detoxification. Interestingly, HPS and PHI homologs are also found in a variety of archaeal strains, and recent biochemical and genome analyses have raised the possibility that the reverse reaction of formaldehyde fixation, i.e., ribulose 5-phosphate (Ru5P) synthesis from fructose 6-phosphate, may function in the biosynthesis of Ru5P in some archaeal strains whose pentose phosphate pathways are imperfect. In this study, we have taken a genetic approach to address this possibility by using the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. This strain possesses a single open reading frame (TK0475) encoding an HPS- and PHI-fused protein. The recombinant HPS-PHI-fused enzyme exhibited the expected HPS and PHI activities in both directions (formaldehyde fixing and Ru5P synthesizing). The TK0475 deletion mutant Δhps-phi-7A did not exhibit any growth in minimal medium, while growth of the mutant strain could be recovered by the addition of nucleosides to the medium. This auxotrophic phenotype together with the catalytic properties of the HPS-PHI-fused enzyme reveal that HPS and PHI are essential for the biosynthesis of Ru5P, the precursor of nucleotides, showing that the RuMP pathway is the only relevant pathway for Ru5P biosynthesis substituting for the classical pentose phosphate pathway missing in this archaeon.

scholarly journals Listeria monocytogenes 6-Phosphogluconolactonase Mutants Induce Increased Activation of a Host Cytosolic Surveillance Pathway

2009 ◽  
Vol 77 (7) ◽  
pp. 3014-3022 ◽  
Author(s):  
Gregory T. Crimmins ◽  
Michael W. Schelle ◽  
Anat A. Herskovits ◽  
Peggy P. Ni ◽  
Benjamin C. Kline ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Pentose Phosphate Pathway ◽  
Deletion Mutant ◽  
Minimal Medium ◽  
Pentose Phosphate ◽  
Wild Type ◽  
Transposon Insertion ◽  
Excess Glucose ◽  
Insertion Mutants

ABSTRACT Infection with wild-type Listeria monocytogenes activates a host cytosolic surveillance response characterized by the expression of beta interferon (IFN-β). We performed a genetic screen to identify L. monocytogenes transposon insertion mutants that induced altered levels of host IFN-β expression. One mutant from this screen induced elevated levels of IFN-β and harbored a Tn917 insertion upstream of lmo0558. This study identified lmo0558 as the 6-phosphogluconolactonase gene (pgl), which encodes the second enzyme in the pentose phosphate pathway. pgl mutant L. monocytogenes accumulated and secreted large amounts of gluconate, likely derived from labile 6-phosphogluconolactone, the substrate of Pgl. The pgl deletion mutant had decreased growth in glucose-limiting minimal medium but grew normally when excess glucose was added. Microarray analysis revealed that the pgl deletion mutant had increased expression of several β-glucosidases, consistent with known inhibition of β-glucosidases by 6-phosphogluconolactone. While growth in macrophages was indistinguishable from that of wild-type bacteria, pgl mutant L. monocytogenes exhibited a 15- to 30-fold defect in growth in vivo. In addition, L. monocytogenes harboring an in-frame deletion of pgl was more sensitive to oxidative stress. This study identified L. monocytogenes pgl and provided the first link between the bacterial pentose phosphate pathway and activation of host IFN-β expression.

scholarly journals Complex Metabolic Phenotypes Caused by a Mutation in yjgF, Encoding a Member of the Highly Conserved YER057c/YjgF Family of Proteins

1998 ◽  
Vol 180 (24) ◽  
pp. 6519-6528 ◽  
Author(s):  
Jodi L. Enos-Berlage ◽  
Mark J. Langendorf ◽  
Diana M. Downs
Keyword(s):  
Pentose Phosphate Pathway ◽  
Biosynthetic Pathway ◽  
Genetic Characterization ◽  
Pentose Phosphate ◽  
Oxidative Pentose Phosphate Pathway ◽  
Phenotypic Characterization ◽  
Reading Frame ◽  
Wide Range ◽  
Isoleucine Biosynthesis

ABSTRACT The oxidative pentose phosphate pathway is required for function of the alternative pyrimidine biosynthetic pathway, a pathway that allows thiamine synthesis in the absence of the PurF enzyme inSalmonella typhimurium. Mutants that no longer required function of the oxidative pentose phosphate pathway for thiamine synthesis were isolated. Further phenotypic analyses of these mutants demonstrated that they were also sensitive to the presence of serine in the medium, suggesting a partial defect in isoleucine biosynthesis. Genetic characterization showed that these pleiotropic phenotypes were caused by null mutations in yjgF, a previously uncharacterized open reading frame encoding a hypothetical 13.5-kDa protein. The YjgF protein belongs to a class of proteins of unknown function that exhibit striking conservation across a wide range of organisms, from bacteria to humans. This work represents the first detailed phenotypic characterization of yjgF mutants in any organism and provides important clues as to the function of this highly conserved class of proteins. Results also suggest a connection between function of the isoleucine biosynthetic pathway and the requirement for the pentose phosphate pathway in thiamine synthesis.

scholarly journals Transaldolase ofMethanocaldococcus jannaschii

Archaea ◽  
2004 ◽  
Vol 1 (4) ◽  
pp. 255-262 ◽  
Author(s):  
Tim Soderberg ◽  
Robert C. Alver
Keyword(s):  
Pentose Phosphate Pathway ◽  
Gel Filtration ◽  
Pentose Phosphate ◽  
Direct Application ◽  
Maximal Velocity ◽  
Native Form ◽  
Methanocaldococcus Jannaschii ◽  
Reading Frame ◽  
Michaelis Constants ◽  
Aldolase Activity

TheMethanocaldococcus jannaschiigenome contains putative genes for all four nonoxidative pentose phosphate pathway enzymes. Open reading frame (ORF) MJ0960 is a member of themipB/talCfamily of ‘transaldolase-like’ genes, so named because of their similarity to the well-characterized transaldolase B gene family. However, recently, it has been reported that both themipBand thetalCgenes fromEscherichia coliencode novel enzymes with fructose-6-phosphate aldolase activity, not transaldolase activity (Schürmann and Sprenger 2001). The same study reports that other members of themipB/talCfamily appear to encode transaldolases. To confirm the function of MJ0960 and to clarify the presence of a nonoxidative pentose phosphate pathway inM. jannaschii, we have cloned ORF MJ0960 fromM. jannaschiigenomic DNA and purified the recombinant protein. MJ0960 encodes a transaldolase and displays no fructose-6-phosphate aldolase activity. It retained full activity for 4 h at 80 °C, and for 3 weeks at 25 °C.Methanocaldococcus jannaschiitransaldolase has a maximal velocity (Vmax) of 1.0 ± 0.2 µmol min–1mg–1at 25 °C, whereasVmax= 12.0 ± 0.5 µmol min–1mg–1at 50 °C. Apparent Michaelis constants at 50 °C wereKm= 0.65 ± 0.09 mM for fructose-6-phosphate andKm= 27.8 ± 4.3 µM for erythrose-4-phosphate. When ribose-5-phosphate replaced erythrose-4-phosphate as an aldose acceptor,Vmaxdecreased twofold, whereas theKmwas 150-fold higher. The molecular mass of the active enzyme is 271 ± 27 kDa as estimated by gel filtration, whereas the predicted monomer size is 23.96 kDa, suggesting that the native form of the protein is probably a decamer. A readily available source of thermophilic pentose phosphate pathway enzymes including transaldolase may have direct application in enzymatic biohydrogen production.

scholarly journals Ribose-5-Phosphate Biosynthesis in Methanocaldococcus jannaschii Occurs in the Absence of a Pentose-Phosphate Pathway

2005 ◽  
Vol 187 (21) ◽  
pp. 7382-7389 ◽  
Author(s):  
Laura L. Grochowski ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Recent Work ◽  
Pentose Phosphate Pathway ◽  
Methanogenic Archaea ◽  
Protein Product ◽  
Pentose Phosphate ◽  
The Other ◽  
Methanocaldococcus Jannaschii ◽  
Cell Extracts ◽  
Ribulose Monophosphate Pathway ◽  
Sugar Phosphates

ABSTRACT Recent work has raised a question as to the involvement of erythrose-4-phosphate, a product of the pentose phosphate pathway, in the metabolism of the methanogenic archaea (R. H. White, Biochemistry 43:7618-7627, 2004). To address the possible absence of erythrose-4-phosphate in Methanocaldococcus jannaschii, we have assayed cell extracts of this methanogen for the presence of this and other intermediates in the pentose phosphate pathway and have determined and compared the labeling patterns of sugar phosphates derived metabolically from [6,6-2H2]- and [U-13C]-labeled glucose-6-phosphate incubated with cell extracts. The results of this work have established the absence of pentose phosphate pathway intermediates erythrose-4-phosphate, xylose-5-phosphate, and sedoheptulose-7-phosphate in these cells and the presence of d-arabino-3-hexulose-6-phosphate, an intermediate in the ribulose monophosphate pathway. The labeling of the d-ara-bino-3-hexulose-6-phosphate, as well as the other sugar-Ps, indicates that this hexose-6-phosphate was the precursor to ribulose-5-phosphate that in turn was converted into ribose-5-phosphate by ribose-5-phosphate isomerase. Additional work has demonstrated that ribulose-5-phosphate is derived by the loss of formaldehyde from d-arabino-3-hexulose-6-phosphate, catalyzed by the protein product of the MJ1447 gene.

scholarly journals Transport and Catabolism of Carbohydrates by Neisseria meningitidis

2016 ◽  
Vol 26 (5) ◽  
pp. 320-332 ◽  
Author(s):  
Meriem Derkaoui ◽  
Ana Antunes ◽  
Jamila Nait Abdallah ◽  
Sandrine Poncet ◽  
Alain Mazé ◽  
...  
Keyword(s):  
Carbon Source ◽  
Transgenic Mice ◽  
Neisseria Meningitidis ◽  
Pentose Phosphate Pathway ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Pentose Phosphate ◽  
Key Enzymes ◽  
The Real ◽  
Genes Encoding

We identified the genes encoding the proteins for the transport of glucose and maltose in <i>Neisseria meningitidis</i> strain 2C4-3. A mutant deleted for <i>NMV_1892</i><i>(glcP)</i> no longer grew on glucose and deletion of <i>NMV_0424</i><i>(malY)</i> prevented the utilization of maltose. We also purified and characterized glucokinase and α-phosphoglucomutase, which catalyze early catabolic steps of the two carbohydrates. <i>N. meningitidis</i> catabolizes the two carbohydrates either via the Entner-Doudoroff (ED) pathway or the pentose phosphate pathway, thereby forming glyceraldehyde-3-P and either pyruvate or fructose-6-P, respectively. We purified and characterized several key enzymes of the two pathways. The genes required for the transformation of glucose into gluconate-6-P and its further catabolism via the ED pathway are organized in two adjacent operons. <i>N. meningitidis</i> also contains genes encoding proteins which exhibit similarity to the gluconate transporter <i>(NMV_2230)</i> and gluconate kinase <i>(NMV_2231)</i> of Enterobacteriaceae and Firmicutes. However, gluconate might not be the real substrate of <i>NMV_2230</i> because <i>N. meningitidi</i>s was not able to grow on gluconate as the sole carbon source. Surprisingly, deletion of <i>NMV_2230</i> stimulated growth in minimal medium in the presence and absence of glucose and drastically slowed the clearance of <i>N. meningitidis</i> cells from transgenic mice after intraperitoneal challenge.

scholarly journals Systematic Identification of Regulators of Oxidative Stress Reveals Non-canonical Roles for Peroxisomal Import and the Pentose Phosphate Pathway

Cell Reports ◽  
2020 ◽  
Vol 30 (5) ◽  
pp. 1417-1433.e7 ◽  
Author(s):  
Michael M. Dubreuil ◽  
David W. Morgens ◽  
Kanji Okumoto ◽  
Masanori Honsho ◽  
Kévin Contrepois ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pentose Phosphate Pathway ◽  
Pentose Phosphate ◽  
Systematic Identification

scholarly journals Geranylgeranylacetone attenuates cerebral ischemia–reperfusion injury in rats through the augmentation of HSP 27 phosphorylation: a preliminary study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kazuya Matsuo ◽  
Kohkichi Hosoda ◽  
Jun Tanaka ◽  
Yusuke Yamamoto ◽  
Taichiro Imahori ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Reperfusion Injury ◽  
Pentose Phosphate Pathway ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Pentose Phosphate ◽  
Cerebral Ischemia Reperfusion ◽  
Hsp27 Phosphorylation ◽  
Cerebral Ischemia Reperfusion Injury ◽  
Preliminary Study

Abstract Background We previously reported that heat shock protein 27 (HSP27) phosphorylation plays an important role in the activation of glucose-6-phosphate dehydrogenase (G6PD), resulting in the upregulation of the pentose phosphate pathway and antioxidant effects against cerebral ischemia–reperfusion injury. The present study investigated the effect of geranylgeranylacetone, an inducer of HSP27, on ischemia–reperfusion injury in male rats as a preliminary study to see if further research of the effects of geranylgeranylacetone on the ischemic stroke was warranted. Methods In all experiments, male Wistar rats were used. First, we conducted pathway activity profiling based on a gas chromatography–mass spectrometry to identify ischemia–reperfusion-related metabolic pathways. Next, we investigated the effects of geranylgeranylacetone on the pentose phosphate pathway and ischemia–reperfusion injury by real-time polymerase chain reaction (RT-PCR), immunoblotting, and G6PD activity, protein carbonylation and infarct volume analysis. Geranylgeranylacetone or vehicle was injected intracerebroventricularly 3 h prior to middle cerebral artery occlusion or sham operation. Results Pathway activity profiling demonstrated that changes in the metabolic state depended on reperfusion time and that the pentose phosphate pathway and taurine-hypotaurine metabolism pathway were the most strongly related to reperfusion among 137 metabolic pathways. RT-PCR demonstrated that geranylgeranylacetone did not significantly affect the increase in HSP27 transcript levels after ischemia–reperfusion. Immunoblotting showed that geranylgeranylacetone did not significantly affect the elevation of HSP27 protein levels. However, geranylgeranylacetone significantly increase the elevation of phosphorylation of HSP27 after ischemia–reperfusion. In addition, geranylgeranylacetone significantly affected the increase in G6PD activity, and reduced the increase in protein carbonylation after ischemia–reperfusion. Accordingly, geranylgeranylacetone significantly reduced the infarct size (median 31.3% vs 19.9%, p = 0.0013). Conclusions As a preliminary study, these findings suggest that geranylgeranylacetone may be a promising agent for the treatment of ischemic stroke and would be worthy of further study. Further studies are required to clearly delineate the mechanism of geranylgeranylacetone-induced HSP27 phosphorylation in antioxidant effects, which may guide the development of new approaches for minimizing the impact of cerebral ischemia–reperfusion injury.

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