Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 2 de 2
Filter
Add more filters










Database
Language
Publication year range
1.
Antimicrob Agents Chemother ; 58(1): 61-70, 2014.
Article in English | MEDLINE | ID: mdl-24126580

ABSTRACT

Moxifloxacin has shown excellent activity against drug-sensitive as well as drug-resistant tuberculosis (TB), thus confirming DNA gyrase as a clinically validated target for discovering novel anti-TB agents. We have identified novel inhibitors in the pyrrolamide class which kill Mycobacterium tuberculosis through inhibition of ATPase activity catalyzed by the GyrB domain of DNA gyrase. A homology model of the M. tuberculosis H37Rv GyrB domain was used for deciphering the structure-activity relationship and binding interactions of inhibitors with mycobacterial GyrB enzyme. Proposed binding interactions were later confirmed through cocrystal structure studies with the Mycobacterium smegmatis GyrB ATPase domain. The most potent compound in this series inhibited supercoiling activity of DNA gyrase with a 50% inhibitory concentration (IC50) of <5 nM, an MIC of 0.03 µg/ml against M. tuberculosis H37Rv, and an MIC90 of <0.25 µg/ml against 99 drug-resistant clinical isolates of M. tuberculosis. The frequency of isolating spontaneous resistant mutants was ∼10(-6) to 10(-8), and the point mutation mapped to the M. tuberculosis GyrB domain (Ser208 Ala), thus confirming its mode of action. The best compound tested for in vivo efficacy in the mouse model showed a 1.1-log reduction in lung CFU in the acute model and a 0.7-log reduction in the chronic model. This class of GyrB inhibitors could be developed as novel anti-TB agents.


Subject(s)
Antitubercular Agents/pharmacology , Antitubercular Agents/therapeutic use , Mycobacterium tuberculosis/pathogenicity , Tuberculosis/drug therapy , Animals , Cell Line , Humans , Mice , Mycobacterium tuberculosis/drug effects , Structure-Activity Relationship
2.
J Med Chem ; 56(21): 8834-48, 2013 Nov 14.
Article in English | MEDLINE | ID: mdl-24088190

ABSTRACT

A pharmacophore-based search led to the identification of thiazolopyridine ureas as a novel scaffold with antitubercular activity acting through inhibition of DNA Gyrase B (GyrB) ATPase. Evaluation of the binding mode of thiazolopyridines in a Mycobacterium tuberculosis (Mtb) GyrB homology model prompted exploration of the side chains at the thiazolopyridine ring C-5 position to access the ribose/solvent pocket. Potent compounds with GyrB IC50 ≤ 1 nM and Mtb MIC ≤ 0.1 µM were obtained with certain combinations of side chains at the C-5 position and heterocycles at the C-6 position of the thiazolopyridine core. Substitutions at C-5 also enabled optimization of the physicochemical properties. Representative compounds were cocrystallized with Streptococcus pneumoniae (Spn) ParE; these confirmed the binding modes predicted by the homology model. The target link to GyrB was confirmed by genetic mapping of the mutations conferring resistance to thiazolopyridine ureas. The compounds are bactericidal in vitro and efficacious in vivo in an acute murine model of tuberculosis.


Subject(s)
Antitubercular Agents/pharmacology , DNA Gyrase/metabolism , Mycobacterium tuberculosis/drug effects , Pyridines/pharmacology , Topoisomerase II Inhibitors/pharmacology , Tuberculosis/drug therapy , Urea/pharmacology , Animals , Antitubercular Agents/administration & dosage , Antitubercular Agents/chemistry , Disease Models, Animal , Dose-Response Relationship, Drug , Mice , Mice, Inbred BALB C , Models, Molecular , Molecular Structure , Mycobacterium tuberculosis/enzymology , Pyridines/administration & dosage , Pyridines/chemistry , Structure-Activity Relationship , Topoisomerase II Inhibitors/administration & dosage , Topoisomerase II Inhibitors/chemistry , Urea/analogs & derivatives , Urea/chemistry
SELECTION OF CITATIONS
SEARCH DETAIL
...