Figure 1.

Label-based chemoproteomic methods for malaria drug target identification. A) Affinity-based protein profiling (AfBPP). Plasmodium parasite lysates are incubated with bead-immobilized compounds. After washes, the ligand-binding proteins can be eluted for MS analysis. B) Activity-based protein profiling (ABPP). Enriched Plasmodium-infected RBCs or the parasite lysates are incubated with an ABPP probe in the presence or absence of drugs. The RBCs are lysed (for intact cells), and a reporter tag (e.g., biotin or fluorescent tags) can be conjugated to the reactive head group via click chemistry. Proteins covalently modified by the probe are enriched using an avidin or streptavidin column for MS analysis. Fluorescently tagged proteins can be visualized by gel electrophoresis. Proteins targeted by the drug will show a deceased signal as the ABPP probe is competed out by the compound.