Identification of potent and selectiveN-myristoyltransferase inhibitors ofPlasmodium vivaxliver stage hypnozoites and schizonts

ABSTRACT New drugs targeting multiple stages of the malaria-causing parasite, Plasmodium , are needed to reduce and eliminate malaria worldwide. N -Myristoyltransferase (NMT) is an essential eukaryotic enzyme, and a validated chemically tractable drug target for malaria. Previous efforts have failed to target NMT owing to the low selectivity for the Plasmodium enzyme compared with human NMTs. Herein, we applied a structure-guided approach using previously reported NMT inhibitors as scaffolds to develop a new generation of Plasmodium vivax NMT ( Pv NMT) targeting compounds. We report a series of compounds with IC 50 values in the nM range and an order of magnitude improved selectivity to Plasmodium NMT over human NMT ( Hs NMT). X-ray co-crystallization of Pv NMT with a representative lead compound, 12b , supported the prevailing hypothesis that a conformational difference in a key tyrosine residue of Pv NMT and Hs NMT drives the selectivity between these enzymes. The compounds were triaged based on their selectivity for Pv NMT. They significantly decreased P. falciparum blood-stage parasite load, with IC 50 values ranging from 0.36 μM to 1.25 μM. The compounds exhibited a dose-dependent inhibition of P. vivax liver stage schizont and hypnozoite infection, consistently, in three different P. vivax isolates with IC 50 values ranging from 2.2 μM to 6 μM and from 1.2 μM to 12 μM. Our data provide evidence that NMT inhibitors could be multistage antimalarials, targeting both dormant and developing liver stage parasites, which is essential for malaria elimination. One Sentence Summary Potent and selective N -myristoyltransferase inhibitors of Plasmodium vivax hypnozoites and schizonts were synthesized and tested.