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The F-type ATP synthase inhibitor bedaquiline (BDQ) is a potent inhibitor of mycobacterial growth and this inhibition cannot be rescued by fermentable carbon sources that would supply ATP by an alternative pathway (substrate level phosphorylation). To gain mechanistic insight into this phenomenon, we employed a metabolic engineering approach. We introduced into Mycobacterium smegmatis an alternative ATP production pathway by substrate-level phosphorylation, specifically through overexpression of trypanosomal acetate:succinate co-enzyme A (CoA) transferase (ASCT). Intriguingly, the overexpression of ASCT partially restored intracellular ATP levels and resulted in acquired tolerance to BDQ growth inhibition at low, but not high concentrations of BDQ. These results implicate intracellular ATP levels in modulating the growth inhibitory activity of BDQ at low concentrations. These findings shed light on the intricate interplay between BDQ and mycobacterial energy metabolism, while also providing a novel tool for the development of next-generation ATP synthase-specific inhibitors targeting mycobacteria. The ATP synthase inhibitor bedaquiline (BDQ) inhibits mycobacterial growth by depleting ATP, with gained tolerance to low BDQ concentrations through metabolic transplantation of trypanosomal SLPHOS pathway. [ABSTRACT FROM AUTHOR]

Abstract: Background: Helicobacter pylori (H. pylori) infection causes various gastrointestinal diseases including gastric cancer. Hence, eradication of this infection could prevent these diseases. The most popular first‐line treatment protocol to eradicate H. pylori is termed “triple therapy” and consists of a proton pump inhibitor (PPI), clarithromycin, and amoxicillin or metronidazole. However, the antibiotics used to treat H. pylori infection are hindered by the antibiotics‐resistant bacteria and by their antimicrobial activity against intestinal bacteria, leading to side effects. Therefore, an alternative treatment with fewer adverse side effects is urgently required to improve the overall eradication rate of H. pylori. Objective: The aim of this study was to assess the effectiveness and mechanism of action of an antitumor agent, intervenolin, and its derivatives as an agent for the treatment of H. pylori infection. Results: We demonstrate that intervenolin, and its derivatives showed selective anti‐H. pylori activity, including antibiotic‐resistant strains, without any effect on intestinal bacteria. We showed that dihydroorotate dehydrogenase, a key enzyme for de novo pyrimidine biosynthesis, is a target and treatment with intervenolin or its derivatives decreased the protein and mRNA levels of H. pylori urease, which protects H. pylori against acidic conditions in the stomach. Using a mouse model of H. pylori infection, oral monotherapy with the intervenolin derivative AS‐1934 had a stronger anti‐H. pylori effect than the triple therapy commonly used worldwide to eradicate H. pylori. Conclusion: AS‐1934 has potential advantages over current treatment options for H. pylori infection. [ABSTRACT FROM AUTHOR]

Plasmodium falciparum's resistance to available antimalarial drugs highlights the need for the development of novel drugs. Pyrimidine de novo biosynthesis is a validated drug target for the prevention and treatment of malaria infection. P. falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the oxidation of dihydroorotate to orotate and utilize ubiquinone as an electron acceptor in the fourth step of pyrimidine de novo biosynthesis. PfDHODH is targeted by the inhibitor DSM265, which binds to a hydrophobic pocket located at the N-terminus where ubiquinone binds, which is known to be structurally divergent from the mammalian orthologue. In this study, we screened 40,400 compounds from the Kyoto University chemical library against recombinant PfDHODH. These studies led to the identification of 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine and its derivatives as a new class of PfDHODH inhibitor. Moreover, the hit compounds identified in this study are selective for PfDHODH without inhibition of the human enzymes. Finally, this new scaffold of PfDHODH inhibitors showed growth inhibition activity against P. falciparum 3D7 with low toxicity to three human cell lines, providing a new starting point for antimalarial drug development. [ABSTRACT FROM AUTHOR]