Computational Approach to study the effect of point mutations in the development of antifungal resistance to Azoles and Flucytosine Drugs in Candida auris
Background: Candida auris is associated with invasive and severe candidemia, multi-drug resistance and high mortalities. Azoles and Flucytosine are commonly used antifungal drugs. Lanosterol alpha-demethylase (ERG11), Uracil phosphoribosyl transferase (FUR1) are two principal proteins involved in ergosterol biosynthesis and pyrimidine metabolism. However, crystal structures of these proteins from C. auris have not yet been established. We constructed structural model of ERG11 and FUR1 proteins for South-African Clade using homology modelling, molecular docking and molecular dynamics simulations. To investigate how point mutations affect drug interaction, we used the same methods on ERG11 mutants (Y132F, K143R) and FUR1 mutants (F211I). Methodology: Homology modelling was used to construct 3D structure of proteins. Reliability of models was analysed by using validation tools. The drug interaction in wild and mutant variants was studied using molecular docking, and binding energy was calculated. Finally, we investigated structural significance of point-mutation between two variants of FUR1 through MD Simulation. Result: Structural models of ERG11 and FUR1 were compared based on binding energy and hydrogen bonding. Few azole compounds showed no effect of mutation on interaction. Further, it was found that binding affinity for 5-fluorocytosine decreases in the mutant variant of FUR1. MD Simulation of wild variant FUR1-5FC complex showed stabilisation till 7ns while mutated complex was stable for 4.5ns. Conclusion: C. auris resistance to antifungal drugs poses a significant risk to public health. The study sheds light on how drug interactions are influenced by mutations and aids in the development of antifungal drugs.