Identification of Selective Inhibitors of Plasmodium N-Myristoyltransferase by High-Throughput Screening

Abstract

New drugs that target Plasmodium species, the causative agents of malaria, are needed. The enzyme N-myristoyltransferase (NMT) is an essential protein, which catalyzes the myristoylation of protein substrates, often to mediate membrane targeting. We screened ∼1.8 million small molecules for activity against Plasmodium vivax (P. vivax) NMT. Hits were triaged based on potency and physicochemical properties and further tested against P. vivax and Plasmodium falciparum (P. falciparum) NMTs. We assessed the activity of hits against human NMT1 and NMT2 and discarded compounds with low selectivity indices. We identified 23 chemical classes specific for the inhibition of Plasmodium NMTs over human NMTs, including multiple novel scaffolds. Cocrystallization of P. vivax NMT with one compound revealed peptide binding pocket binding. Other compounds show a range of potential modes of action. Our data provide insight into the activity of a collection of selective inhibitors of Plasmodium NMT and serve as a starting point for subsequent medicinal chemistry efforts.

Microfibrous Extracellular Matrix Changes the Liver Hepatocyte Energy Metabolism via Integrins

“…Human liver cell lines derived from hepatic carcinomas such as HepG2 and Huh7 have been widely applied in toxicity test, drug screening, and physiological studies [36][37][38] . However, discrepancies exist between the cell lines and hepatocytes in the liver, making many in vitro results irreproducible in subsequent animal and clinical trials 39,40 .…”

“…Human liver cell lines derived from hepatic carcinomas, including HepG2 and Huh7, have been widely applied in pharmaco-toxicology, drug screening, and physiological studies due to availability. − However, significant differences exist between the cell lines and hepatocytes in the liver, making the in vitro results often irreproducible in subsequent trials. , To improve the predictivity and reproducibility of cell line-based assays, the discrepancies need to be minimized. Accumulating evidence suggests that the conventional way to culture the cells in vitro can be a cause of the discrepancies. , Cells grown in a 2D monolayer in a container or on a surface cannot recapitulate the in vivo microenvironment .…”

High-Throughput Screening for the Discovery of Enzyme Inhibitors

“…Intuitively, a higher Z ′ factor (a larger difference between the signals obtained for positive and negative controls and/or smaller standard deviations in their signals) is expected to result in a higher hit rate, although this is also dependent on the statistical cutoff used to determine a hit . In order to confirm whether this expected correlation existed, the confirmed % hit rate for campaigns identified in Table , ,,,,,− Table , ,,,,,− ,,,,,,,− ,,, and several additional papers − was plotted as a function of Z ′ factor (Figure ).…”

Beyond phosphorylation: Putative roles of post-translational modifications in Plasmodium sexual stages

“…Mediators of PTMs are considered attractive targets for therapeutic intervention for various diseases including malaria [ 5 ]. Although protein kinases have been the predominant area of focus, there is emerging interest in disruptors of ubiquitylation [ 6 , 7 ] and myristoylation [ 8 ] pathways. Here we examine proteomic studies covering PTMs (excluding phosphorylation) in asexual stages and by comparing to the gametocyte proteome studies, we explore the possible roles for these understudied PTMs in transmission biology.…”