Tuberculosis Thymidine Monophosphate Kinase Research Articles

Design of Thymidine Analogues Targeting Thymidilate Kinase ofMycobacterium tuberculosis

We design here new nanomolar antituberculotics, inhibitors of Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt), by means of structure-based molecular design. 3D models of TMPKmt-inhibitor complexes have been prepared from the crystal structure of TMPKmt cocrystallized with the natural substrate deoxythymidine monophosphate (dTMP) (1GSI) for a training set of 15 thymidine analogues (TMDs) with known activity to prepare a QSAR model of interaction establishing a correlation between the free energy of complexation and the biological activity. Subsequent validation of the predictability of the model has been performed with a 3D QSAR pharmacophore generation. The structural information derived from the model served to design new subnanomolar thymidine analogues. From molecular modeling investigations, the agreement between free energy of complexation (ΔΔG com) and K i values explains 94% of the TMPKmt inhibition (pK i = −0.2924ΔΔG com + 3.234; R 2 = 0.94) by variation of the computed ΔΔG com and 92% for the pharmacophore (PH4) model (pK i = 1.0206 × pK i pred − 0.0832, R 2 = 0.92). The analysis of contributions from active site residues suggested substitution at the 5-position of pyrimidine ring and various groups at the 5′-position of the ribose. The best inhibitor reached a predicted K i of 0.155 nM. The computational approach through the combined use of molecular modeling and PH4 pharmacophore is helpful in targeted drug design, providing valuable information for the synthesis and prediction of activity of novel antituberculotic agents.

Identification of novel antimycobacterial chemical agents through the in silico multi-conformational structure-based drug screening of a large-scale chemical library

The increasing prevalence of drug-resistant tuberculosis, which is resistant to effective multiple antibiotic, presents a major global health threat. The thymidine monophosphate kinase (TMPK) of Mycobacterium tuberculosis (M. tuberculosis), which is an essential enzyme for the maintenance of the thymidine triphosphate pools, is considered an attractive target for the development of effective antibiotics against tuberculosis. In this study, we attempted to identify novel chemical compounds that specifically target the M. tuberculosis TMPK (mtTMPK). We performed in silico structure-based drug screening using the crystal structure data of mtTMPK and a large-scale virtual compound library, which is composed of 6,192,930 chemicals. Through a three-step screening method using the DOCK and GOLD, we identified ten chemical compounds that were predicted to have high binding affinity to the active site cleft of the mtTMPK. We then evaluated the antibiotic effects of these chemical compounds on model mycobacteria strains. As a result, we found that a chemical compound, K10, completely inhibited the growth of Mycobacterium vanbaalenii (M. vanbaalenii) and Mycobacterium smegmatis (M. smegmatis). Moreover, K10 does not exhibit any toxic effects on the growth of enterobacteria and mammalian cells. The structural and experimental information regarding this novel chemical compound, K10, is likely to be useful for the hit-to-lead optimization of new antibiotics for the treatment of tuberculosis.