Real-time measurements of ATP dynamics via ATeams in reveal drug-class-specific response patterns.

, caused by the parasite (), remains one of the greatest public health burdens for humankind. Due to its pivotal role in parasite survival, the energy metabolism of is an interesting target for drug design. To this end, analysis of the central metabolite adenosine triphosphate (ATP) is of great interest.

An Optimized Dihydrodibenzothiazepine Lead Compound (SBI-0797750) as a Potent and Selective Inhibitor of Plasmodium falciparum and P. vivax Glucose 6-Phosphate Dehydrogenase 6-Phosphogluconolactonase.

In , the first two and rate-limiting enzymes of the pentose phosphate pathway, glucose 6-phosphate dehydrogenase (G6PD) and the 6-phosphogluconolactonase, are bifunctionally fused to a unique enzyme named GluPho, differing structurally and mechanistically from the respective human orthologs. Consistent with the enzyme's essentiality for malaria parasite proliferation and propagation, human G6PD deficiency has immense impact on protection against severe malaria, making GluPho an attractive antimalarial drug target. Herein we report on the optimized lead compound -(((2R,4S)-1-cyclobutyl-4-hydroxypyrrolidin-2-yl)methyl)-6-fluoro-4-methyl-11-oxo-10,11-dihydrodibenzo[b,f][1,4]thiazepine-8-carboxamide (SBI-0797750), a potent and fully selective GluPho inhibitor with robust nanomolar activity against recombinant GluPho, G6PD, and P.

Structure and Function of Redox-Sensitive Superfolder Green Fluorescent Protein Variant.

Genetically encoded green fluorescent protein (GFP)-based redox biosensors are widely used to monitor specific and dynamic redox processes in living cells. Over the last few years, various biosensors for a variety of applications were engineered and enhanced to match the organism and cellular environments, which should be investigated. In this context, the unicellular intraerythrocytic parasite , the causative agent of malaria, represents a challenge, as the small size of the organism results in weak fluorescence signals that complicate precise measurements, especially for cell compartment-specific observations.

Peroxide Antimalarial Drugs Target Redox Homeostasis in Infected Red Blood Cells.

causes the most lethal form of malaria. Peroxide antimalarials based on artemisinin underpin the frontline treatments for malaria, but artemisinin resistance is rapidly spreading. Synthetic peroxide antimalarials, known as ozonides, are in clinical development and offer a potential alternative.

Ferredoxin-NADP Reductase-Catalyzed Redox Cycling of Plasmodione Generates Both Predicted Key Drug Metabolites: Implication for Antimalarial Drug Development.

Plasmodione (PD) is a potent antimalarial redox-active 3-benzyl-menadione acting at low nanomolar range concentrations on different malaria parasite stages. The specific bioactivation of PD was proposed to occur via a cascade of redox reactions starting from one-electron reduction and then benzylic oxidation, leading to the generation of several key metabolites including corresponding benzylic alcohol (PD-bzol, for PD benzhydrol) and 3-benzoylmenadione (PDO, for PD oxide). In this study, we showed that the benzylic oxidation of PD is closely related to the formation of a benzylic semiquinone radical, which can be produced under two conditions: UV photoirradiation or catalysis by apicoplast ferredoxin-NADP reductase (FNR) redox cycling in the presence of oxygen and the parent PD.

Insights into the intracellular localization, protein associations and artemisinin resistance properties of Plasmodium falciparum K13.

The emergence of artemisinin (ART) resistance in Plasmodium falciparum intra-erythrocytic parasites has led to increasing treatment failure rates with first-line ART-based combination therapies in Southeast Asia. Decreased parasite susceptibility is caused by K13 mutations, which are associated clinically with delayed parasite clearance in patients and in vitro with an enhanced ability of ring-stage parasites to survive brief exposure to the active ART metabolite dihydroartemisinin. Herein, we describe a panel of K13-specific monoclonal antibodies and gene-edited parasite lines co-expressing epitope-tagged versions of K13 in trans.

Stable Integration and Comparison of hGrx1-roGFP2 and sfroGFP2 Redox Probes in the Malaria Parasite Plasmodium falciparum.

Studying redox metabolism in malaria parasites is of great interest for understanding parasite biology, parasite-host interactions, and mechanisms of drug action. Genetically encoded fluorescent redox sensors have recently been described as powerful tools for determining the glutathione-dependent redox potential in living parasites. In the present study, we genomically integrated and expressed the ratiometric redox sensors hGrx1-roGFP2 (human glutaredoxin 1 fused to reduction-oxidation sensitive green fluorescent protein) and sfroGFP2 (superfolder roGFP2) in the cytosol of NF54- attB blood-stage Plasmodium falciparum parasites.