Evolutionary divergence from IGPS proteins suggests a novel apicoplast biogenesis function for <i>Pf</i>AMR1.

(A) Conservation of active-site residues between IGPS and IGPS-like proteins. Sequences of IGPS homologs identified in V. brassicaformis and P. falciparum and known IGPS enzymes from E. coli and Saccharomyces cerevisiae were aligned. Active-site residues identified from structure-function studies in IGPS enzymes are listed. dCatalytic residues. See also S6 Fig. (B) Schematic of IGPS and IGPS-like protein loss in P. falciparum and Cryptosporidium parvum, respectively. (C) Complementation of an E. coli trpC mutant (trpC9800) with IGPS and IGPS-like proteins from V. brassicaformis and P. falciparum grown on minimal media (M9) + antibiotic resistance (carbenicillin) + and trp. Empty vector condition contains only antibiotic resistance. BL21 Star (DE3) strain was used for the WT condition. (D) Same complementation as in panel C but grown without trp. AMR, apicoplast-minus IPP-rescued; AS, anthranilate synthase; IGPS, indole-3-glycerol phosphate synthase; IPP, isopentenyl diphosphate; PRT, phosphoribosyltransferase; trp, tryptophan; TS, tryptophan synthase; WT, wild-type.