Fig. 6. T. gondii tachyzoites salvage Pan synthesis intermediates and use these for Pan synthesis.

a Scheme of the Pan biosynthesis pathway, highlighting the ketopantoate hydroxymethyltransferase - ketopantoate reductase (KPHMT-KPR) and the pantoate beta alanine ligase (PBAL). Salvage of α-ketoisovalerate and pantoate as precursors for Pan synthesis is shown. See Fig. 1 for abbreviations. b GC-MS Measurement of relative intracellular Pan levels in RH parental parasites following incubation in medium without Pan supplemented with valine (Val, 3 mM) and β-alanine (β-Ala, 2 mM) (n = 3, mean and SD, 2-sided Student’s t test). c Metabolite structures highlighting the theoretical incorporation of labeled atoms (red circles) from stable isotope labeled ¹³C₃/¹⁵N-β-Ala into Pan and into CoA. Exact masses of the parental ion (M0), and heavy stable isotope labeled (M4) are presented in black and red, respectively. d LC-MS analysis of the relative isotopologue (M0, M4) abundance of RH parental derived metabolites following incubation in medium with 3 mM ¹³C₃/¹⁵N-β-Ala or 100 μM ¹³C₃/¹⁵N-Pan (n = 4, mean and SD, 2-sided Student’s t test). e LC-MS analysis of Pan isotopologue (M0 to M7) distribution of RH parental, bcat-ko, kphmt-kpr-ko, pbal-ko derived metabolites following growth over 40 h in regular DMEM, DMEM − Pan +5 % dialyzed FBS supplemented with metabolites as indicated: α-ketoisovalerate, pantoate, ¹³C₃/¹⁵N-β-Ala (each at 0.8 mM). Statistical analysis was carried out on the percentage of labeling shown in supplementary data (n = 3, mean and SD, 2-sided Student’s t test). n number of independent biological replicates. Source data are provided as a Source Data file.