PNP and bacterial infectious disease: We usedmetronidazole because the drug is extensively used to treat G. lamblia, Trichomonas varginalis, and bacterial infections.33 Moreover,data on a few metronidazole interacting proteins were also availableto cross-validate the screen.27,34 The screen identifiedgenes encoding proteins that interact with metronidazole, e.g., thioredoxinreductase and purine nucleoside phosphorylase, thus reproducing describeddrug targets, and identified new protein interacting candidates.