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

Nowadays kinin is the most effective antimalarial drug and its used as an alternative in malaria treatment. However, toxicity of quinine restrict its use as an antimalarial drug. Lipophilicity and long half-life (t½) of quinine that reach 10-20 hours are responsible for its toxicity. The aim of this research is to obtain more polar quinine derivatives by means of hydrogen peroxide reactions to reduce the toxicity. The reactions using hydrogen peroxyde is performed analogously to the procedures reported in the literature. Extract of pure anhydrous kinin is purified in coloumn chromatography followed by structure elucidation. Synthetic product is tested in vitro against Plasmodium falciparum. The characterization of reaction products is performed with proton (1H) and carbon 13 (13C) nuclear magnetic resonance (NMR) spectroscopy. It showed that the reaction using reagents led to epoxidation of vinyl substituents of chinuclidine ring with 61,08% yields. Antimalarial test against Plasmodium falciparum obtained 1.250-2.500 μg/mL of IC50 value. The IC50 values indicated that the synthesis products were not potential for malaria treatment.

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Mitochondrial type II NADH dehydrogenase of Plasmodium falciparum is dispensable and not the functional target of putative NDH2 quinolone inhibitors

10.1101/436881 ◽

2018 ◽

Author(s):

Hangjun Ke ◽

Suresh M. Ganesan ◽

Swati Dass ◽

Joanne M. Morrisey ◽

Sovitj Pou ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Antimalarial Drug ◽

Drug Target ◽

Nadh Dehydrogenase ◽

Antimalarial Activity ◽

Reductase Activity ◽

Proton Pumping ◽

Type Ii ◽

Long Time ◽

Specific Inhibitors

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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Biochemical and Structural Characterization of Selective Allosteric Inhibitors of the Plasmodium falciparum Drug Target, Prolyl-tRNA-synthetase

ACS Infectious Diseases ◽

10.1021/acsinfecdis.6b00078 ◽

2016 ◽

Vol 3 (1) ◽

pp. 34-44 ◽

Cited By ~ 20

Author(s):

Stephen Nakazawa Hewitt ◽

David M. Dranow ◽

Benjamin G. Horst ◽

Jan A. Abendroth ◽

Barbara Forte ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Structural Characterization ◽

Drug Target ◽

Trna Synthetase ◽

Allosteric Inhibitors

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Characterization of Plasmodium falciparum NEDD8 and identification of cullins as its substrates

Scientific Reports ◽

10.1038/s41598-020-77001-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Manish Bhattacharjee ◽

Navin Adhikari ◽

Renu Sudhakar ◽

Zeba Rizvi ◽

Divya Das ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Drug Target ◽

Parasite Development ◽

Wild Type ◽

Post Translational Modifications ◽

Apicomplexan Parasites ◽

Cellular Processes ◽

Ring E3 ◽

Physiological Substrates

AbstractA variety of post-translational modifications of Plasmodium falciparum proteins, including phosphorylation and ubiquitination, are shown to have key regulatory roles during parasite development. NEDD8 is a ubiquitin-like modifier of cullin-RING E3 ubiquitin ligases, which regulates diverse cellular processes. Although neddylation is conserved in eukaryotes, it is yet to be characterized in Plasmodium and related apicomplexan parasites. We characterized P. falciparum NEDD8 (PfNEDD8) and identified cullins as its physiological substrates. PfNEDD8 is a 76 amino acid residue protein without the C-terminal tail, indicating that it can be readily conjugated. The wild type and mutant (Gly75Ala/Gly76Ala) PfNEDD8 were expressed in P. falciparum. Western blot of wild type PfNEDD8-expressing parasites indicated multiple high molecular weight conjugates, which were absent in the parasites expressing the mutant, indicating conjugation of NEDD8 through Gly76. Immunoprecipitation followed by mass spectrometry of wild type PfNEDD8-expressing parasites identified two putative cullins. Furthermore, we expressed PfNEDD8 in mutant S. cerevisiae strains that lacked endogenous NEDD8 (rub1Δ) or NEDD8 conjugating E2 enzyme (ubc12Δ). The PfNEDD8 immunoprecipitate also contained S. cerevisiae cullin cdc53, further substantiating cullins as physiological substrates of PfNEDD8. Our findings lay ground for investigation of specific roles and drug target potential of neddylation in malaria parasites.

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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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Glucose-6-phosphate dehydrogenase–6-phosphogluconolactonase: a unique bifunctional enzyme from Plasmodium falciparum

Biochemical Journal ◽

10.1042/bj20110170 ◽

2011 ◽

Vol 436 (3) ◽

pp. 641-650 ◽

Cited By ~ 32

Author(s):

Esther Jortzik ◽

Boniface M. Mailu ◽

Janina Preuss ◽

Marina Fischer ◽

Lars Bode ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Pentose Phosphate Pathway ◽

Drug Target ◽

Pentose Phosphate ◽

Bifunctional Enzyme ◽

Functional Differences ◽

Glucose 6 Phosphate Dehydrogenase ◽

First Time ◽

Human Rbcs

The survival of malaria parasites in human RBCs (red blood cells) depends on the pentose phosphate pathway, both in Plasmodium falciparum and its human host. G6PD (glucose-6-phosphate dehydrogenase) deficiency, the most common human enzyme deficiency, leads to a lack of NADPH in erythrocytes, and protects from malaria. In P. falciparum, G6PD is combined with the second enzyme of the pentose phosphate pathway to create a unique bifunctional enzyme named GluPho (glucose-6-phosphate dehydrogenase–6-phosphogluconolactonase). In the present paper, we report for the first time the cloning, heterologous overexpression, purification and kinetic characterization of both enzymatic activities of full-length PfGluPho (P. falciparum GluPho), and demonstrate striking structural and functional differences with the human enzymes. Detailed kinetic analyses indicate that PfGluPho functions on the basis of a rapid equilibrium random Bi Bi mechanism, where the binding of the second substrate depends on the first substrate. We furthermore show that PfGluPho is inhibited by S-glutathionylation. The availability of recombinant PfGluPho and the major differences to hG6PD (human G6PD) facilitate studies on PfGluPho as an excellent drug target candidate in the search for new antimalarial drugs.

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