A pyrophosphatase regulating polyphosphate metabolism in acidocalcisomes is essential for Trypanosoma brucei virulence in mice
| Autor: | Théo Baltz, Felix A. Ruiz, Guillaume Lemercier, Benoit Espiau, Roberto Docampo, Mauricio Vieira, Shuhong Luo, Norbert Bakalara |
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| Rok vydání: | 2003 |
| Předmět: |
Osmosis
Time Factors Protozoan Proteins Biochemistry Substrate Specificity chemistry.chemical_compound Mice Polyphosphates Magnesium Cloning Molecular Pyrophosphatases chemistry.chemical_classification Adenosine Triphosphatases Pyrophosphatase Chromatography biology Virulence Hydrolysis Hydrogen-Ion Concentration Cosmids Recombinant Proteins Amino acid Acid Anhydride Hydrolases Zinc Phenotype Chromatography Gel RNA Interference Blotting Western Immunoblotting Molecular Sequence Data Trypanosoma brucei brucei Trypanosoma brucei Transfection Phosphates Endopeptidases Protein oligomerization Animals Amino Acid Sequence Molecular Biology RNA Double-Stranded Dose-Response Relationship Drug Sequence Homology Amino Acid Cell Biology Metabolism biology.organism_classification Molecular biology Protein Structure Tertiary Acidocalcisome Kinetics Microscopy Electron Enzyme chemistry Calcium |
| Zdroj: | The Journal of biological chemistry. 279(5) |
| ISSN: | 0021-9258 |
| Popis: | We report the functional characterization of a soluble pyrophosphatase (TbVSP1), which localizes to acidocalcisomes, a vesicular acidic compartment of Trypanosoma brucei. Depending on the pH and the cofactors Mg(2+) or Zn(2+), both present in the compartment, the enzyme hydrolyzes either inorganic pyrophosphate (PP(i)) (k(cat) = 385 s(-1)) or tripolyP (polyP(3)) and polyphosphate (polyP) of 28 residues (polyP(28)) with k(cat) values of 52 and 3.5 s(-1), respectively. An unusual N-terminal domain of 160 amino acids, containing a putative calcium EF-hand-binding domain, is involved in protein oligomerization. Using double-stranded RNA interference methodology, we produced an inducible bloodstream form (BF) deficient in the TbVSP1 protein (BFiVSP1). The long-chain polyP levels of these mutants were reduced by 60%. Their phenotypes revealed a deficient polyP metabolism, as indicated by their defective response to phosphate starvation and hyposmotic stress. BFiVSP1 did not cause acute virulent infection in mice, demonstrating that TbVSP1 is essential for growth of bloodstream forms in the mammalian host. |
| Databáze: | OpenAIRE |
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