In-silico study of antituberculous activity of Zn-pyrazinamide in pyrazinamidase

Abstract

Tuberculosis is caused by Mycobacterium tuberculosis and is one of the leading causes of death. Treatment with pyrazinamide depends on the formation of the bioactive species, pyrazinoic acid (POA), catalyzed by the enzyme pyrazinamidase (PZAse). New mutant strains show resistance to PZA, therefore, it is necessary to search for new drugs. Metallodrugs can offer a synergistic effect on the biological activity of the metal and the drug. Recent studies by our group show anti-tuberculosis activity of pyrazinamide coordinated with Zn, however, the mechanism of action is unknown. In this work, an in-silico study was carried out in three stages: Quantum mechanical, molecular docking and molecular dynamics simulations. ZnPZA (Egap = 4.12 eV) presented greater chemical reactivity than PZA (Egap = 4.97 eV). Greater binding energy was found in ZnPZA-PZAse (-6.98 kcal/mol) than in PZA-PZAse (-6.48 kcal/mol). RMSD and RMSF show stability in PZA-PZAse and ZnPZA-PZAse dockings. Hydrogen bonds interaction of ZnPZA with the catalytic amino acids Asp8 and Lys96 occurs for 83 and 40 ns, respectively. It is concluded that ZnPZA could serve as a transporter of PZA to the active site of PZAse, to promote the production of POA and the antituberculous effect; however, further experimental studies are needed.