In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 113, No. 7 ( 2016-02-16)
Abstract:
Mycobacterium tuberculosis is a significant source of global morbidity and mortality. Moxifloxacin and other fluoroquinolones are important therapeutic agents for the treatment of tuberculosis, particularly multidrug-resistant infections. To guide the development of new quinolone-based agents, it is critical to understand the basis of drug action against M. tuberculosis gyrase and how mutations in the enzyme cause resistance. Therefore, we characterized interactions of fluoroquinolones and related drugs with WT gyrase and enzymes carrying mutations at GyrA A90 and GyrA D94 . M. tuberculosis gyrase lacks a conserved serine that anchors a water–metal ion bridge that is critical for quinolone interactions with other bacterial type II topoisomerases. Despite the fact that the serine is replaced by an alanine (i.e., GyrA A90 ) in M. tuberculosis gyrase, the bridge still forms and plays a functional role in mediating quinolone–gyrase interactions. Clinically relevant mutations at GyrA A90 and GyrA D94 cause quinolone resistance by disrupting the bridge–enzyme interaction, thereby decreasing drug affinity. Fluoroquinolone activity against WT and resistant enzymes is enhanced by the introduction of specific groups at the C7 and C8 positions. By dissecting fluoroquinolone–enzyme interactions, we determined that an 8-methyl-moxifloxacin derivative induces high levels of stable cleavage complexes with WT gyrase and two common resistant enzymes, GyrA A90V and GyrA D94G . 8-Methyl-moxifloxacin was more potent than moxifloxacin against WT M. tuberculosis gyrase and displayed higher activity against the mutant enzymes than moxifloxacin did against WT gyrase. This chemical biology approach to defining drug–enzyme interactions has the potential to identify novel drugs with improved activity against tuberculosis.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.1525055113
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2016
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
