Helicases − feasible antimalarial drug target for Plasmodium falciparum

AbstractThe battle against malaria has been substantially impeded by the recurrence of drug resistance in Plasmodium falciparum, the deadliest human malaria parasite. To counter the problem, novel antimalarial drugs are urgently needed, especially those that target unique pathways of the parasite, since they are less likely to have side effects. The mitochondrial type II NADH dehydrogenase of P. falciparum, PfNDH2 (PF3D7_0915000), has been considered a good prospective antimalarial drug target for over a decade, since malaria parasites lack the conventional multi-subunit NADH dehydrogenase, or Complex I, present in the mammalian mitochondrial electron transport chain (mtETC). Instead, Plasmodium parasites contain a single subunit NDH2, which lacks proton pumping activity and is absent in humans. A significant amount of effort has been expended to develop PfNDH2 specific inhibitors, yet the essentiality of PfNDH2 has not been convincingly verified. Herein, we knocked out PfNDH2 in P. falciparum via a CRISPR/Cas9 mediated approach. Deletion of PfNDH2 does not alter the parasite’s susceptibility to multiple mtETC inhibitors, including atovaquone and ELQ-300. We also show that the antimalarial activity of the fungal NDH2 inhibitor HDQ and its new derivative CK-2-68 is due to inhibition of the parasite cytochrome bc1 complex rather than PfNDH2. These compounds directly inhibit the ubiquinol-cytochrome c reductase activity of the malarial bc1 complex. Our results call into question the validity of PfNDH2 as an antimalarial drug target.ImportanceFor a long time, PfNDH2 has been considered an attractive antimalarial drug target. However, the conclusion that PfNDH2 is essential was based on preliminary and incomplete data. Here we generate a PfNDH2 KO (knockout) parasite in the blood stages of Plasmodium falciparum, showing that the gene is not essential. We also show that previously reported PfNDH2-specific inhibitors kill the parasites primarily via targeting the cytochrome bc1 complex, not PfNDH2. Overall, we provide genetic and biochemical data that help to resolve a long-debated issue in the field regarding the potential of PfNDH2 as an antimalarial drug target.

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Comparison of Efficacies of Cysteine Protease Inhibitors against Five Strains of Plasmodium falciparum

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.3.949-951.2001 ◽

2001 ◽

Vol 45 (3) ◽

pp. 949-951 ◽

Cited By ~ 60

Author(s):

Ajay Singh ◽

Philip J. Rosenthal

Keyword(s):

Plasmodium Falciparum ◽

Protease Inhibitors ◽

Cysteine Protease ◽

Antimalarial Drug ◽

Drug Target ◽

Antimalarial Drugs ◽

Cross Resistance ◽

Cysteine Protease Inhibitors ◽

Antimalarial Agents ◽

Parasite Strains

ABSTRACT Falcipain-2, a cysteine protease and essential hemoglobinase ofPlasmodium falciparum, is a potential antimalarial drug target. We compared the falcipain-2 sequences and sensitivities to cysteine protease inhibitors of five parasite strains that differ markedly in sensitivity to established antimalarial drugs. The sequence of falcipain-2 was highly conserved, and the sensitivities of all of the strains to falcipain-2 inhibitors were very similar. Thus, cross-resistance between cysteine protease inhibitors and other antimalarial agents is not expected in parasites that are now circulating and falcipain-2 remains a promising chemotherapeutic target.

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Plasmodium falciparum Niemann-Pick Type C1-Related Protein is a Druggable Target Required for Parasite Membrane Homeostasis

10.1101/371484 ◽

2018 ◽

Cited By ~ 2

Author(s):

Eva S. Istvan ◽

Sudipta Das ◽

Suyash Bhatnagar ◽

Josh R. Beck ◽

Edward Owen ◽

...

Keyword(s):

Electron Microscopy ◽

Plasmodium Falciparum ◽

Plasma Membrane ◽

Small Molecule ◽

Antimalarial Drug ◽

Drug Target ◽

Related Protein ◽

Immuno Electron Microscopy ◽

Increased Sensitivity ◽

Niemann Pick

AbstractPlasmodium parasites possess a protein with homology to Niemann-Pick Type C1 proteins (Plasmodium falciparum Niemann-Pick Type C1-Related protein, PfNCR1). We isolated parasites with resistance-conferring mutations in PfNCR1 during selections with three diverse small-molecule antimalarial compounds and show that the mutations are causative for compound resistance. PfNCR1 protein knockdown results in severely attenuated growth and confers hypersensitivity to the compounds. Compound treatment or protein knockdown leads to increased sensitivity of the parasite plasma membrane (PPM) to the amphipathic glycoside saponin and engenders digestive vacuoles (DVs) that are small and malformed. Immuno-electron microscopy and split-GFP experiments localize PfNCR1 to the PPM. Our experiments show that PfNCR1 activity is critically important for the composition of the PPM and is required for DV biogenesis, suggesting PfNCR1 as a novel antimalarial drug target.

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Characterization of Plasmodium falciparum 6-Phosphogluconate Dehydrogenase as an Antimalarial Drug Target

Journal of Molecular Biology ◽

10.1016/j.jmb.2018.07.030 ◽

2018 ◽

Vol 430 (21) ◽

pp. 4049-4067 ◽

Cited By ~ 5

Author(s):

Kristina Haeussler ◽

Karin Fritz-Wolf ◽

Max Reichmann ◽

Stefan Rahlfs ◽

Katja Becker

Keyword(s):

Plasmodium Falciparum ◽

Antimalarial Drug ◽

Drug Target ◽

Phosphogluconate Dehydrogenase

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Glutathione Reductase of Plasmodium Falciparum as an Antimalarial Drug Target of Methylene Blue

Biophysical Journal ◽

10.1016/j.bpj.2014.11.337 ◽

2015 ◽

Vol 108 (2) ◽

pp. 55a-56a

Author(s):

Socheata Lim ◽

Judith H. Prieto

Keyword(s):

Methylene Blue ◽

Plasmodium Falciparum ◽

Glutathione Reductase ◽

Antimalarial Drug ◽

Drug Target

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Co-expression of the Plasmodium falciparum molecular chaperone, PfHsp70, improves the heterologous production of the antimalarial drug target GTP cyclohydrolase I, PfGCHI

Protein Expression and Purification ◽

10.1016/j.pep.2011.01.005 ◽

2011 ◽

Vol 77 (2) ◽

pp. 159-165 ◽

Cited By ~ 10

Author(s):

Linda L. Stephens ◽

Addmore Shonhai ◽

Gregory L. Blatch

Keyword(s):

Plasmodium Falciparum ◽

Molecular Chaperone ◽

Antimalarial Drug ◽

Drug Target ◽

Heterologous Production ◽

Gtp Cyclohydrolase I ◽

Gtp Cyclohydrolase

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Re-refinement of Plasmodium falciparum orotidine 5′-monophosphate decarboxylase provides a clearer picture of an important malarial drug target

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x18010610 ◽

2018 ◽

Vol 74 (10) ◽

pp. 664-668 ◽

Cited By ~ 2

Author(s):

Walter R. P. Novak ◽

Korbin H. J. West ◽

Lucy M. D. Kirkman ◽

Gabriel S. Brandt

Keyword(s):

Public Health ◽

Plasmodium Falciparum ◽

Drug Design ◽

Electron Density ◽

Antimalarial Drug ◽

Drug Target ◽

Antimalarial Drugs ◽

Important Advance ◽

Structure Based Drug Design ◽

Monophosphate Decarboxylase

The development of antimalarial drugs remains a public health priority, and the orotidine 5′-monophosphate decarboxylase from Plasmodium falciparum (PfOMPDC) has great potential as a drug target. The crystallization of PfOMPDC with substrate bound represents an important advance for structure-based drug-design efforts [Tokuoka et al. (2008), J. Biochem. 143, 69–78]. The complex of the enzyme bound to the substrate OMP (PDB entry 2za1) would be of particular utility in this regard. However, re-refinement of this structure of the Michaelis complex shows that the bound ligand is the product rather than the substrate. Here, the re-refinement of a set of three structures, the apo enzyme and two versions of the product-bound form (PDB entries 2za1, 2za2 and 2za3), is reported. The improved geometry and fit of these structures to the observed electron density will enhance their utility in antimalarial drug design.

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A specific non-bisphosphonate inhibitor of the bifunctional farnesyl/geranylgeranyl diphosphate synthase in malaria parasites

10.1101/134338 ◽

2017 ◽

Cited By ~ 1

Author(s):

Jolyn E. Gisselberg ◽

Zachary Herrera ◽

Lindsey Orchard ◽

Manuel Llinás ◽

Ellen Yeh

Keyword(s):

Plasmodium Falciparum ◽

Physicochemical Properties ◽

Small Molecule ◽

Antimalarial Drug ◽

Drug Target ◽

Drug Targets ◽

Geranylgeranyl Diphosphate Synthase ◽

Geranylgeranyl Diphosphate ◽

Malaria Parasites ◽

Starting Point

SummaryIsoprenoid biosynthesis is essential for Plasmodium falciparum (malaria) parasites and contains multiple validated antimalarial drug targets, including a bifunctional farnesyl and geranylgeranyl diphosphate synthase (FPPS/GGPPS). We identified MMV019313 as an inhibitor of PfFPPS/GGPPS. Though PfFPPS/GGPPS is also inhibited by a class of bisphosphonate drugs, MMV019313 has significant advantages for antimalarial drug development. MMV019313 has superior physicochemical properties compared to charged bisphosphonates that have poor bioavailability and strong bone affinity. We also show that it is highly selective for PfFPPS/GGPPS and showed no activity against human FPPS or GGPPS. Inhibition of PfFPPS/GGPPS by MMV019313, but not bisphosphonates, was disrupted in an S228T variant, demonstrating that MMV019313 and bisphosphonates have distinct modes-of-inhibition against PfFPPS/GGPPS. Altogether MMV019313 is the first specific, non-bisphosphonate inhibitor of PfFPPS/GGPPS. Our findings uncover a new small molecule binding site in this important antimalarial drug target and provide a promising starting point for development of Plasmodium-specific FPPS/GGPPS inhibitors.

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