Drug repurposing: Fusidic acid as a potential inhibitor of M. tuberculosis FtsZ polymerization - Insight from DFT calculations, molecular docking and molecular dynamics simulations.

Filamentous Temperature Sensitive Mutant Z (FtsZ), an important cell division protein in bacteria, has been validated as a potential target for antibiotics development. Citric acid has been found to inhibit the polymerization of Mycobacterium tuberculosis (MTB) FtsZ and several other drugs have been predicted as potential inhibitors through a gene ontology-based drug repurposing approach. An in-depth study on four of the predicted drugs; Fusidic acid (FusA), l-tryptophan, Carbamic acid, and 2-(3-guanidinophenyl)-3-mercaptopropanoic acid, as potential inhibitors of MTB-FtsZ polymerization was conducted using Citric acid as reference compound. The applied in silico methods involve DFT calculations, molecular docking and molecular dynamics simulations. DFT approach was applied to evaluate selectivity and stability properties of the predicted drugs. Calculated parameters including non-linear optical properties, charge distribution and electrostatic potential analyses enabled selectivity prediction of these potential drugs. DFT-based descriptors revealed FusA as the most potent compound, even more reactive than the referenced compound, Citric acid, which is also supported from the molecular docking study. Parameters including MM/PBSA binding free energies, RMSD, RMSF, RoG and hydrogen bond analysis also support FusA as the best potential MTB-FtsZ polymerization inhibitor, that forms a stable complex with the protein and impose greatest level of rigidity to the protein.