How do the Mutations in PfK13 Protein Promote Anti-malarial Drug Resistance?

Plasmodium falciparum develops resistance to artemisinin upon exposure to the anti-malarial drug. Various mutations in the Plasmodium falciparum Kelch13 (PfK13) protein such as Y493H, R539T, I543T, and C580Y have been associated with antimalarial drug resistance. (Ariey et al., Nature, 2014, 505, 50-55) These mutations impede the regular ubiquitination process that eventually invokes drug resistance. However, the relationship between the mutation and the mechanism of drug resistance has not yet been fully elucidated. The comparative protein dynamics are studied by performing the classical molecular dynamics (MD) simulations and subsequent analysis of the trajectories adopting root-means-square fluctuations, the secondary-structure predictions and the dynamical cross-correlation matrix analysis tools. Here we observed that the mutations in the Kelch-domain does not have any structural impact on the mutated site, however, it significantly alters the overall dynamics of the protein. The loop-region of the BTB-domain especially for Y493H and C580Y mutants are found to have the enhanced dynamical fluctuations. The enhanced fluctuations in the BTB-domain could affect the protein-protein (PfK13-Cullin) binding interactions in the ubiquitination process and eventually leads to anti-malarial drug resistance.