Abstract
We report the results of a solid-state
31P nuclear magnetic resonance (NMR) spectroscopic investigation of the acidocalcisome organelles from
Trypanosoma brucei (bloodstream form),
Trypanosoma cruzi and
Leishmania major (insect forms). The spectra are characterized by a broad envelope of spinning sidebands having isotropic chemical shifts at ∼0, −7 and −21 ppm. These resonances are assigned to orthophosphate, terminal (α) phosphates of polyphosphates and bridging (β) phosphates of polyphosphates, respectively. The average polyphosphate chain length is ∼3.3 phosphates. Similar results were obtained with whole
L. major promastigotes.
31P NMR spectra of living
L. major promastigotes recorded under conventional solution NMR conditions had spectral intensities reduced with respect to solution-state NMR spectra of acid extracts, consistent with the invisibility of the solid-state phosphates. These results show that all three parasites contain large stores of condensed phosphates which can be visualized by using magic-angle spinning NMR techniques.
