neo-Inositol polyphosphates in the amoeba Entamoeba histolytica
Autor(en): | Martin, JB Laussmann, T Bakker-Grunwald, T Vogel, G Klein, G |
Stichwörter: | Biochemistry & Molecular Biology; C-13-NMR; DICTYOSTELIUM; FREE-LIVING AMEBA; IDENTIFICATION; NMR; PENTAKISPHOSPHATE; PHOSPHATES; SCYLLO-INOSITOL; SPECTRA; TETRAKISPHOSPHATE | Erscheinungsdatum: | 2000 | Herausgeber: | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC | Journal: | JOURNAL OF BIOLOGICAL CHEMISTRY | Volumen: | 275 | Ausgabe: | 14 | Startseite: | 10134 | Seitenende: | 10140 | Zusammenfassung: | We have reexamined the structure of inositol phosphates resent in trophozoites of the parasitic amoeba Entamoeba histolytica and show here that, rather than being myo-inositol derivatives (Martin, J.-B., Bakker-Grunwald, T., and Klein, G. (1993) fur. J, Biochem 214, 711-718), these compounds belong to a new class of inositol phosphates in which the cyclitol isomer is neo-inositol. The structures of neo-inositol hexakisphosphate, 2-diphospho-neo-inositol pentakisphosphate, and 2,5-bisdiphospho-neo-inositol tetrakisphosphate, which are present in E. histolytica at concentrations of 0.08-0.36 mM, were solved by two-dimensional P-31-H-1 NMR spectroscopy. No evidence for the co-existence of their myo-inositol counterparts has been found. These neo-inositol compounds were not substrates of 6-diphospho-inositol pentakisphosphate Fi-kinase, an enzyme purified from Dictyostelium discoideum that phosphorylates 6-diphospho-myo-inositol pentakisphosphate and more slowly also myo-inositol hexakisphosphate, specifically on position 5. Because preliminary data indicate that large amounts of the same neo-inositol phosphate and diphosphate esters are also present in another primitive amoeba, Phreatamoeba balamuthi, the occurrence of high concentrations of neo-inositol polyphosphates may be much more general than previously thought. |
ISSN: | 00219258 | DOI: | 10.1074/jbc.275.14.10134 |
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