Project description:Exploration and Characterization of the Antimalarial Activity of Cyclopropyl Carboxamides that Target the Mitochondrial Protein, Cytochrome b
Project description:Deep mutational scanning is a powerful method for exploring the mutational fitness landscape of proteins. Its adaptation to anti-CRISPR proteins, which are natural CRISPR-Cas inhibitors and key players in the co-evolution of microbes and phages, facilitates their characterization and optimization. Here, we developed a robust anti-CRISPR deep mutational scanning pipeline in Escherichia coli that combines synthetic gene circuits based on CRISPR interference with flow cytometry coupled sequencing and mathematical modeling. Using this pipeline, we characterized comprehensive single point mutation libraries for AcrIIA4 and AcrIIA5, two potent inhibitors of CRISPR-Cas9. The resulting mutational fitness landscapes revealed considerable mutational tolerance for both Acrs, suggesting an intrinsic redundancy with respect to Cas9 inhibitory features, and – for AcrIIA5 – indicated mutations that boost Cas9 inhibition. Subsequent in vitro characterization suggested that the observed differences in inhibitory potency between mutant inhibitors were mostly due to changes in binding affinity rather than protein expression levels. Finally, to demonstrate that our pipeline can inform Acrs-based genome editing applications, we employed a selected subset of mutant inhibitors to increase CRISPR-Cas9 target specificity by modulating Cas9 activity. Taken together, our work establishes deep mutational scanning as a powerful method for anti-CRISPR protein characterization and optimization.
Project description:<p>Characterizing the mode of action of antimalarial compounds that emerge from high-throughput phenotypic screens is central to understanding how parasite resistance to these drugs can emerge. Here, we have employed untargeted metabolomics to inform on the mechanism of action of antimalarial leads with different speed of kill profiles being developed by the Novartis Institute of Tropical Diseases (NITD). Time-resolved global changes in malaria parasite metabolite profiles upon drug treatment were quantified using liquid chromatography-based mass spectrometry (LC-MS) and compared to untreated controls. Using this approach, we confirmed previously reported metabolomics profiles of the fast-killing (2.5 h) drug dihydroartemisinin (DHA) and the slower killing atovaquone (ATQ). A slow acting antimalarial lead from NITD of imidazolopiperazine (IZP) class, GNF179, elicited little or no discernable metabolic change in malaria parasites in the same 2.5 h window of drug exposure. In contrast, fast killing drugs, DHA and the spiroindolone (NITD246) elicited similar metabolomic profiles both in terms of kinetics and content. DHA and NITD246 induced peptide losses consistent with disruption of haemoglobin catabolism and also interfered with the pyrimidine biosynthesis pathway. Two members of the recently described novel class of antimalarial agents of the 5-aryl-2-amino-imidazothiadiazole (ITD) class also exhibited a fast-acting profile that also featured peptide losses indicative of disrupted haemoglobin catabolism. Our screen demonstrates that structurally unrelated, fast acting antimalarial compounds generate similar biochemical signatures in <em>Plasmodium</em> pointing to a common mechanism associated with rapid parasite death. These profiles may be used to identify and possibly predict the mode of action of other fast-acting drug candidates.</p>
Project description:Acquired antimalarial drug resistance produces treatment failures and has led to periods of global disease resurgence. In P. falciparum, resistance is known to arise through genome-level changes such as mutations and gene duplications. We now report an epigenetic resistance mechanism involving genes responsible for the plasmodial surface anion channel, a nutrient channel that also transports ions and antimalarial compounds at the host erythrocyte membrane. Two blasticidin S-resistant lines exhibited markedly reduced expression of clag Mutant FCB-br1 and wild-type FCB samples were hybridized to seven arrays (biological repeats) using forward (n=2) and reverse (n=5) fluoro.
Project description:Acquired antimalarial drug resistance produces treatment failures and has led to periods of global disease resurgence. In P. falciparum, resistance is known to arise through genome-level changes such as mutations and gene duplications. We now report an epigenetic resistance mechanism involving genes responsible for the plasmodial surface anion channel, a nutrient channel that also transports ions and antimalarial compounds at the host erythrocyte membrane. Two blasticidin S-resistant lines exhibited markedly reduced expression of clag
Project description:Comparative transcriptome analysis of resistant, moderately resistant and susceptible wheat in response to Puccina striiformis tritici