Fig. 2.

Contributions of Cho, Etn, and Ser to P. falciparum PL metabolism. P. falciparum-iRBCs (3D7 and pfpmtΔ strains) were incubated 48 h in culture medium supplemented with 10% human serum in the presence of 20 µM Cho-d₉, 10 µM Etn-d₄, and 140 µM Ser-d₃. After incubation, PLs and reaction intermediates were quantified by LC-MS/MS. The relative contributions of Cho-d₉, Etn-d₄, and Ser-d₃ in the 3D7 strain to biosynthesis of PLs (A) and reaction intermediates (B) are presented. The color code used here is conserved for all figures. Results are shown as means ± SD (n≥3). C: Summary diagram of PL biosynthesis pathways of 3D7 strain showing the sources of PL and reaction intermediates. Values with SD are given in supplemental Table 1. D, E: Relative precursor contributions to PC and PE (D) and biosynthesis (E). For PE, distinction was made between PE coming from Ser decarboxylation and the CDP-Etn-dependent pathway (Ser decarboxylase + Kennedy) and PE coming from PS decarboxylation (PSD). PS was synthesized by a single biosynthesis pathway from Ser and is not represented here. F: Contributions of Cho-d₉, Etn-d₄, and Ser-d₃ to biosynthesis of PL in the pfpmtΔ strain. Results are shown as means ± SD (n = 3).