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evolution
the enzyme belongs to the DHH family of phosphoesterases. Polyphosphatases Ppx1, Ppn1, Ddp1, and Ppn2 show distinct substrate specificities and levels of endo- and exopolyphosphatase activities, as well as distinct patterns of stimulation by metal ions. The differences in the mode of polyphosphate hydrolysis, substrate specificity, metal ion dependence and cell localization suggest distinct roles of these enzymes in yeast
evolution
the enzyme belongs to the PPX/GppA phosphatase family (pfam02541) that consists of PPX (EC 3.6.1.11) and guanosine pentaphosphate phosphohydrolase (GppA, EC 3.6.1.40) enzymes
evolution
the exopolyphosphatase belongs to the ASKHA protein superfamily
evolution
the Nudix superfamily (Pfam PF00293) is found in archaea, bacteria, eukaryotes and viruses and includes pyrophosphohydrolases of nucleotide sugars and alcohols, nucleoside and deoxynucleoside triphosphates ([d]NTPs), dinucleoside polyphosphates, dinucleotide coenzymes and capped RNAs. Trypanosoma brucei has five Nudix hydrolases
evolution
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the enzyme belongs to the DHH family of phosphoesterases. Polyphosphatases Ppx1, Ppn1, Ddp1, and Ppn2 show distinct substrate specificities and levels of endo- and exopolyphosphatase activities, as well as distinct patterns of stimulation by metal ions. The differences in the mode of polyphosphate hydrolysis, substrate specificity, metal ion dependence and cell localization suggest distinct roles of these enzymes in yeast
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evolution
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the enzyme belongs to the PPX/GppA phosphatase family (pfam02541) that consists of PPX (EC 3.6.1.11) and guanosine pentaphosphate phosphohydrolase (GppA, EC 3.6.1.40) enzymes
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evolution
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the Nudix superfamily (Pfam PF00293) is found in archaea, bacteria, eukaryotes and viruses and includes pyrophosphohydrolases of nucleotide sugars and alcohols, nucleoside and deoxynucleoside triphosphates ([d]NTPs), dinucleoside polyphosphates, dinucleotide coenzymes and capped RNAs. Trypanosoma brucei has five Nudix hydrolases
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malfunction
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bacteria lacking PPX exhibit increased resistance to complement-mediated killing. Loss of PPX leads to decrease in alternative pathway activation on bacterial surface
malfunction
PPX1 genetic ablation does not produce a dramatic phenotype
malfunction
deficiency of exopolyphosphatase results in decelerated growth during logarithmic-phase in axenic cultures, and tolerance to the cell wall-active drug isoniazid. The enzyme-deficient mutant shows a significant survival defect in activated human macrophages and reduced persistence in the lungs of guinea pigs
malfunction
analysis of single ppx- or ppk- mutants and of the double mutant, demonstrate a relationship between these genes and the survival capacity
malfunction
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PPX1 genetic ablation does not produce a dramatic phenotype
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malfunction
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deficiency of exopolyphosphatase results in decelerated growth during logarithmic-phase in axenic cultures, and tolerance to the cell wall-active drug isoniazid. The enzyme-deficient mutant shows a significant survival defect in activated human macrophages and reduced persistence in the lungs of guinea pigs
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metabolism
inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
metabolism
polyphosphate kinase (PPK) is the principal source of polyphosphate in most bacteria, whereas exopolyphosphatases (PPX) are mainly responsible for the degradation of polyphosphate
metabolism
the enzyme PPN1 shows only exopolyphosphatase activity
metabolism
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inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
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metabolism
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inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
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metabolism
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the enzyme PPN1 shows only exopolyphosphatase activity
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metabolism
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inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
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metabolism
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inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
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metabolism
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inorganic polyphosphate, exopolyphosphatase, and Pho84-like transporters may be involved in copper resistance in Metallosphaera sedula DSM 5348. Existence of a polyphosphate-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment
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metabolism
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polyphosphate kinase (PPK) is the principal source of polyphosphate in most bacteria, whereas exopolyphosphatases (PPX) are mainly responsible for the degradation of polyphosphate
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physiological function
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the biochemical activity of PPX is necessary for interactions with the complement
physiological function
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exopolyphosphatase activity is regulated during mitochondrial respiration and plays a role in adenosine-5-triphosphate synthesis in hard tick embryos
physiological function
exopolyphosphatase is required for long-term survival of Mycobacterium tuberculosis in necrotic lung lesion
physiological function
deletion mutants of exopolyphosphatases Ppx1, Ppx2 and the double knockout mutant all exhibit increased capacity to accumulate polyphosphate. Ppx1 and double mutants show decreased accumulation of ppGpp, an alarmone molecule. The lack of ppx gene products results in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of polyphosphate is critical for Ppx genes in Campylobacter jejuni pathophysiology. Both Ppx1 and Ppx2 mutants are resistant to human complement-mediated killing. The double mutant mutant is sensitive. The serum susceptibility does not occur in the presence of MgCl2 and EGTA. The chicken serum does not have any effect on the mutants' survival. The observed serum susceptibility is not related to surface capsule and lipooligosaccharide structures
physiological function
double deletion mutants of exopolyphosphatases Ppx1/Ppx2 and the double knockout mutant all exhibit increased capacity to accumulate polyphosphate. Ppx1 and double mutants show decreased accumulation of ppGpp, an alarmone molecule. The lack of ppx gene products results in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of polyphosphate is critical for Ppx genes in Campylobacter jejuni pathophysiology. Both Ppx1 and Ppx2 mutants are resistant to human complement-mediated killing. The double mutant mutant is sensitive. The serum susceptibility does not occur in the presence of MgCl2 and EGTA. The chicken serum does not have any effect on the mutants' survival. The observed serum susceptibility is not related to surface capsule and lipooligosaccharide structures
physiological function
exopolyphosphatase Ppx is involved in the production of virulence factors associated with both acute infection (e.g. motility-promoting factors, blue/green pigment production, C6-C12 quorum-sensing homoserine lactones) and chronic infection (e.g. rhamnolipids, biofilm formation). Pseudomonas aeruginosa maintains consistently proper levels of Ppx regardless of environmental conditions. A mutant strain lacking Ppx activity does not grow in phosphate-deficient medium and the survival after 8 or 24 h declines by 25-30% of the initial value
physiological function
strong constitutive overexpression of exopolyphosphatase PPN1 results in 28- and 11fold increase in activity compared to the PPN1 mutant and wild-type strains, respectively. The content of acid-soluble polyphosphate decreases about 6fold and the content of acid-insoluble polyphosphate decreases about 2.5fold in the cells of the transformant compared to the mutant strain
physiological function
exopolyphosphatase (PPX) enzymes degrade inorganic polyphosphate (poly-P), which is essential for the survival of microbial cells in response to external stresses. Inorganic polyphosphate (poly-P), comprising a few to hundreds of orthophosphate residues linked by high-energy phosphoanhydride bonds, is found in virtually all living cells
physiological function
NHs can participate in polyphosphate homeostasis and therefore may help control polyphosphate levels in glycosomes, cytosol and nuclei of Trypanosoma brucei. Endopolyphosphatase (PPN) activity cleaves internal phosphoanhydride bonds generating shorter polyphosphate molecules. Nudix hydrolase 4 (TbNH4 or TbDcp2) is a mRNA de-capping enzyme that removes the 5' cap from processed mRNAs, EC 3.6.1.62
physiological function
NHs can participate in polyphosphate homeostasis and therefore may help control polyphosphate levels in glycosomes, cytosol and nuclei of Trypanosoma brucei. Hydrolysis of polyphosphate with release of phosphate occurs by the activity of a cytosolic exopolyphosphatase (PPX)
physiological function
the exopolyphosphatase of Escherichia coli processively and completely hydrolyses long polyphosphate chains to ortho-phosphate. Polyphosphate plays a remarkable role in pathogenesis, survival and stress tolerance
physiological function
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double deletion mutants of exopolyphosphatases Ppx1/Ppx2 and the double knockout mutant all exhibit increased capacity to accumulate polyphosphate. Ppx1 and double mutants show decreased accumulation of ppGpp, an alarmone molecule. The lack of ppx gene products results in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of polyphosphate is critical for Ppx genes in Campylobacter jejuni pathophysiology. Both Ppx1 and Ppx2 mutants are resistant to human complement-mediated killing. The double mutant mutant is sensitive. The serum susceptibility does not occur in the presence of MgCl2 and EGTA. The chicken serum does not have any effect on the mutants' survival. The observed serum susceptibility is not related to surface capsule and lipooligosaccharide structures
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physiological function
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deletion mutants of exopolyphosphatases Ppx1, Ppx2 and the double knockout mutant all exhibit increased capacity to accumulate polyphosphate. Ppx1 and double mutants show decreased accumulation of ppGpp, an alarmone molecule. The lack of ppx gene products results in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of polyphosphate is critical for Ppx genes in Campylobacter jejuni pathophysiology. Both Ppx1 and Ppx2 mutants are resistant to human complement-mediated killing. The double mutant mutant is sensitive. The serum susceptibility does not occur in the presence of MgCl2 and EGTA. The chicken serum does not have any effect on the mutants' survival. The observed serum susceptibility is not related to surface capsule and lipooligosaccharide structures
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physiological function
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exopolyphosphatase is required for long-term survival of Mycobacterium tuberculosis in necrotic lung lesion
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physiological function
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exopolyphosphatase (PPX) enzymes degrade inorganic polyphosphate (poly-P), which is essential for the survival of microbial cells in response to external stresses. Inorganic polyphosphate (poly-P), comprising a few to hundreds of orthophosphate residues linked by high-energy phosphoanhydride bonds, is found in virtually all living cells
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physiological function
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NHs can participate in polyphosphate homeostasis and therefore may help control polyphosphate levels in glycosomes, cytosol and nuclei of Trypanosoma brucei. Hydrolysis of polyphosphate with release of phosphate occurs by the activity of a cytosolic exopolyphosphatase (PPX)
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physiological function
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NHs can participate in polyphosphate homeostasis and therefore may help control polyphosphate levels in glycosomes, cytosol and nuclei of Trypanosoma brucei. Endopolyphosphatase (PPN) activity cleaves internal phosphoanhydride bonds generating shorter polyphosphate molecules. Nudix hydrolase 4 (TbNH4 or TbDcp2) is a mRNA de-capping enzyme that removes the 5' cap from processed mRNAs, EC 3.6.1.62
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additional information
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a homology model of paPpx in a closed conformation is constructed by comparative modeling, molecular dynamic simulations, overview. Docking study with bound metals and/or ADP defining the N-paPpx(1-314) model in open conformation as receptor. Enzyme electrostatic potential calculations
additional information
homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
additional information
substrate binding structure analysis, different computational approaches, site-direct mutagenesis and kinetic data are applied to understand the relationship between structure and function of exopolyphosphatase. Enzyme residue H378 is proposed as a fundamental gatekeeper for the recognition of long chain polyphosphate. Implication of H378 protonation state, overview. Electrostatic and energy calculations and molecular docking study, molecular dynamics simulations, overview. The frontal surface of the protein has a clear predominance of electropositive potential and the minimum binding energies are also obtained in that surface. This is favored by interaction with R166,K197, H382, G380, and K414. Other favorable region is formed by residues K353, K428, K429, K430 and Q431 in the joint of domains I and IV. On the contrary, the binding energies of the back side of the protein surface are unfavorable to bind polyphosphate, consistent with a predominance of electronegative potential. Indeed, ecPpx is characterized by a clear division between electropositive (frontal) and electronegative (back) potential
additional information
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substrate binding structure analysis, different computational approaches, site-direct mutagenesis and kinetic data are applied to understand the relationship between structure and function of exopolyphosphatase. Enzyme residue H378 is proposed as a fundamental gatekeeper for the recognition of long chain polyphosphate. Implication of H378 protonation state, overview. Electrostatic and energy calculations and molecular docking study, molecular dynamics simulations, overview. The frontal surface of the protein has a clear predominance of electropositive potential and the minimum binding energies are also obtained in that surface. This is favored by interaction with R166,K197, H382, G380, and K414. Other favorable region is formed by residues K353, K428, K429, K430 and Q431 in the joint of domains I and IV. On the contrary, the binding energies of the back side of the protein surface are unfavorable to bind polyphosphate, consistent with a predominance of electronegative potential. Indeed, ecPpx is characterized by a clear division between electropositive (frontal) and electronegative (back) potential
additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
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additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
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additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
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additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
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additional information
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homology modeling structure modelling, Aquifex aeolicus PPX structure (PDB ID 1T6C) is used as the template, overview
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