scholarly journals Biochemical characterization of Arabidopsis APYRASE family reveals their roles in regulating endomembrane NDP/NMP homoeostasis

2015 ◽  
Vol 472 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Tsan-Yu Chiu ◽  
Jeemeng Lao ◽  
Bianca Manalansan ◽  
Dominique Loqué ◽  
Stanley J. Roux ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Nucleoside Triphosphate ◽  
Nucleoside Diphosphatase ◽  
Nucleoside Triphosphatase

The seven apyrase enzymes from Arabidopsis localize to the plant endomembrane. Our analyses indicate that five members (AtAPY1, 2, 4, 5 and 6) exhibit lumenal NDPase (nucleoside diphosphatase) activities whereas AtAPY3 has NTPase (nucleoside triphosphatase) activity. AtAPY7 displayed no nucleoside triphosphate diphosphohydrolases (NTPDase) activity.

scholarly journals Identification and characterization of mutations in the UPF1 gene that affect nonsense suppression and the formation of the Upf protein complex but not mRNA turnover.

1996 ◽  
Vol 16 (10) ◽  
pp. 5491-5506 ◽  
Author(s):  
Y Weng ◽  
K Czaplinski ◽  
S W Peltz
Keyword(s):  
Mrna Decay ◽  
Rna Binding ◽  
Biochemical Characterization ◽  
Translation Termination ◽  
Nonsense Suppression ◽  
Nucleoside Triphosphate ◽  
Rich Region ◽  
Amino Terminal ◽  
Nonsense Mediated Mrna Decay

To understand the relationship between translation and mRNA decay, we have been studying how premature translation termination accelerates the degradation of mRNAs. In the yeast Saccharomyces cerevisiae, the Upf1 protein (Upf1p), which contains a cysteine- and histidine-rich region and nucleoside triphosphate hydrolysis and helicase motifs, was shown to be a trans-acting factor in this decay pathway. A UPF1 gene disruption results in the stabilization of nonsense-containing mRNAs and leads to a nonsense suppression phenotype. Biochemical analysis of the wild-type Upf1p demonstrated that it has RNA-dependent ATPase, RNA helicase, and RNA binding activities. In the work described in the accompanying paper (Y. Weng, K. Czaplinski, and S. W. Peltz, Mol. Cell. Biol. 16:5477-5490, 1996) mutations in the helicase region of Upf1p that inactivated its mRNA decay function but prevented suppression of leu2-2 and tyr7-1 nonsense alleles are identified. On the basis of these results, we suggested that Upf1p is a multifunctional protein involved in modulating mRNA decay and translation termination at nonsense codons. If this is true, we predict that UPF1 mutations with the converse phenotype should be identified. In this report, we describe the identification and biochemical characterization of mutations in the amino-terminal cysteine- and histidine-rich region of Upf1p that have normal nonsense-mediated mRNA decay activities but are able to suppress leu2-2 and tyr7-1 nonsense alleles. Biochemical characterization of these mutant proteins demonstrated that they have altered RNA binding properties. Furthermore, using the two-hybrid system, we characterized the Upf1p-Upf2p interactions and demonstrated that Upf2p interacts with Upf3p. Mutations in the cysteine- and histidine-rich region of Upf1p abolish Upf1p-Upf2p interaction. On the basis of these results, the role of the Upf complex in nonsense-mediated mRNA decay and nonsense suppression is discussed.

Trypanosoma brucei brucei: Biochemical characterization of ecto-nucleoside triphosphate diphosphohydrolase activities

2007 ◽  
Vol 115 (4) ◽  
pp. 315-323 ◽  
Author(s):  
Milane de Souza Leite ◽  
Rachel Thomaz ◽  
Fábio Vasconcelos Fonseca ◽  
Rogério Panizzutti ◽  
Anibal E. Vercesi ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Biochemical Characterization ◽  
Nucleoside Triphosphate ◽  
Trypanosoma Brucei Brucei ◽  
Nucleoside Triphosphate Diphosphohydrolase

Kinetic and biochemical characterization of Trypanosoma evansi nucleoside triphosphate diphosphohydrolase

2015 ◽  
Vol 153 ◽  
pp. 98-104 ◽  
Author(s):  
Paulo Henrique Exterchoter Weiss ◽  
Franciane Batista ◽  
Glauber Wagner ◽  
Maria de Lourdes Borba Magalhães ◽  
Luiz Claudio Miletti
Keyword(s):  
Biochemical Characterization ◽  
Trypanosoma Evansi ◽  
Nucleoside Triphosphate ◽  
Nucleoside Triphosphate Diphosphohydrolase

scholarly journals E-NTPDases: Possible Roles on Host-Parasite Interactions and Therapeutic Opportunities

2021 ◽  
Vol 11 ◽  
Author(s):  
Lisvane Paes-Vieira ◽  
André Luiz Gomes-Vieira ◽  
José Roberto Meyer-Fernandes
Keyword(s):  
Trichomonas Vaginalis ◽  
Biochemical Characterization ◽  
Divalent Cations ◽  
Parasite Clearance ◽  
Nucleoside Triphosphate ◽  
Host Parasite Interactions ◽  
Antiparasitic Drugs ◽  
Host Parasite ◽  
Hydrolysis Of

Belonging to the GDA1/CD39 protein superfamily, nucleoside triphosphate diphosphohydrolases (NTPDases) catalyze the hydrolysis of ATP and ADP to the monophosphate form (AMP) and inorganic phosphate (Pi). Several NTPDase isoforms have been described in different cells, from pathogenic organisms to animals and plants. Biochemical characterization of nucleotidases/NTPDases has revealed the existence of isoforms with different specificities regarding divalent cations (such as calcium and magnesium) and substrates. In mammals, NTPDases have been implicated in the regulation of thrombosis and inflammation. In parasites, such as Trichomonas vaginalis, Trypanosoma spp., Leishmania spp., Schistosoma spp. and Toxoplasma gondii, NTPDases were found on the surface of the cell, and important processes like growth, infectivity, and virulence seem to depend on their activity. For instance, experimental evidence has indicated that parasite NTPDases can regulate the levels of ATP and Adenosine (Ado) of the host cell, leading to the modulation of the host immune response. In this work, we provide a comprehensive review showing the involvement of the nucleotidases/NTPDases in parasites infectivity and virulence, and how inhibition of NTPDases contributes to parasite clearance and the development of new antiparasitic drugs.

scholarly journals Characterization of Agrobacterium tumefaciens PPKs reveals the formation of oligophosphorylated products up to nucleoside nona-phosphates

2020 ◽  
Vol 104 (22) ◽  
pp. 9683-9692
Author(s):  
Celina Frank ◽  
Attila Teleki ◽  
Dieter Jendrossek
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Biochemical Characterization ◽  
Physiological Function ◽  
Adenine Nucleotides ◽  
Nucleoside Triphosphate ◽  
Granule Formation ◽  
Key Points ◽  
Uridine Nucleotides

Abstract Agrobacterium tumefaciens synthesizes polyphosphate (polyP) in the form of one or two polyP granules per cell during growth. The A. tumefaciens genome codes for two polyphosphate kinase genes, ppk1AT and ppk2AT, of which only ppk1AT is essential for polyP granule formation in vivo. Biochemical characterization of the purified PPK1AT and PPK2AT proteins revealed a higher substrate specificity of PPK1AT (in particular for adenine nucleotides) than for PPK2AT. In contrast, PPK2AT accepted all nucleotides at comparable rates. Most interestingly, PPK2AT catalyzed also the formation of tetra-, penta-, hexa-, hepta-, and octa-phosphorylated nucleosides from guanine, cytosine, desoxy-thymidine, and uridine nucleotides and even nona-phosphorylated adenosine. Our data—in combination with in vivo results—suggest that PPK1AT is important for the formation of polyP whereas PPK2AT has the function to replenish nucleoside triphosphate pools during times of enhanced demand. The potential physiological function(s) of the detected oligophosphorylated nucleotides await clarification. Key points •PPK1ATand PPK2AThave different substrate specificities, •PPK2ATis a subgroup 1 member of PPK2s, •PPK2ATcatalyzes the formation of polyphosphorylated nucleosides

scholarly journals Leishmania amazonensis: Biological and biochemical characterization of ecto-nucleoside triphosphate diphosphohydrolase activities

2006 ◽  
Vol 114 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Carla M. Pinheiro ◽  
Erica S. Martins-Duarte ◽  
Rodrigo B. Ferraro ◽  
André Luíz Fonseca de Souza ◽  
Marta T. Gomes ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Leishmania Amazonensis ◽  
Nucleoside Triphosphate ◽  
Nucleoside Triphosphate Diphosphohydrolase

Plant Pathology Diagnosed by X-Ray Microanalysis

1987 ◽  
Vol 45 ◽  
pp. 974-975
Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang
Keyword(s):  
Electron Microscopy ◽  
Plant Pathology ◽  
Biochemical Characterization ◽  
Nutrient Deficiency ◽  
Green Leaf ◽  
Parasitic Infestation ◽  
X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

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