TY - JOUR
T1 - Crystal structure and stability of gyrase-fluoroquinolone cleaved complexes from Mycobacterium tuberculosis
AU - Blower, Tim R.
AU - Williamson, Benjamin H.
AU - Kerns, Robert J.
AU - Berger, James M.
N1 - Funding Information:
We thank Dr. Jon Schuermann [NE-CAT (Northeastern Collaborative Access Team), Advanced Photon Source] and Dr. Craig Ogata [GM/CA@APS (General Medical Sciences and Cancer Institutes Structural Biology Facility at the Advanced Photon Source)] for advice during data collection, Alexia Miller for in silico modeling support, Dr. Matthew Kitching (University of Manchester) for expertise on drug molecules and figures, and Prof. Karl Drlica for extensive advice and critical reading of the manuscript. This work was supported by NIH Grant AI87671 (to R.J.K.) and NIH National Cancer Institute Grant R01-CA077373 (to J.M.B.). T.R.B. was supported by a European Molecular Biology Organization Long-Term Fellowship. This work is based in part upon research conducted at the NE-CAT beamlines, which are funded by the National Institute of General Medical Sciences from the NIH (Grant P41 GM103403). The Pilatus 6M detector on 24-ID-C beamline is funded by NIH, Office of Research Infrastructure Programs, High-End Instrumentation Grant S10 RR029205. This work is also based in part upon research conducted at the GM/CA@APS beamlines, which have been funded in whole or in part with federal funds from National Cancer Institute Grant ACB-12002 and National Institute of General Medical Sciences Grant AGM-12006. This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DEAC02-06CH11357.
PY - 2016/2/16
Y1 - 2016/2/16
N2 - Mycobacterium tuberculosis (Mtb) infects one-third of the world's population and in 2013 accounted for 1.5 million deaths. Fluoroquinolone antibacterials, which target DNA gyrase, are critical agents used to halt the progression from multidrug-resistant tuberculosis to extensively resistant disease; however, fluoroquinolone resistance is emerging and new ways to bypass resistance are required. To better explain known differences in fluoroquinolone action, the crystal structures of the WT Mtb DNA gyrase cleavage core and a fluoroquinolone-sensitized mutant were determined in complex with DNA and five fluoroquinolones. The structures, ranging from 2.4- to 2.6-Å resolution, show that the intrinsically low susceptibility of Mtb to fluoroquinolones correlates with a reduction in contacts to the water shell of an associated magnesium ion, which bridges fluoroquinolone-gyrase interactions. Surprisingly, the structural data revealed few differences in fluoroquinolone- enzyme contacts from drugs that have very different activities against Mtb. By contrast, a stability assay using purified components showed a clear relationship between ternary complex reversibility and inhibitory activities reported with cultured cells. Collectively, our data indicate that the stability of fluoroquinolone/DNA interactions is a major determinant of fluoroquinolone activity and that moieties that have been appended to the C7 position of different quinolone scaffolds do not take advantage of specific contacts that might be made with the enzyme. These concepts point to new approaches for developing quinolone-class compounds that have increased potency against Mtb and the ability to overcome resistance.
AB - Mycobacterium tuberculosis (Mtb) infects one-third of the world's population and in 2013 accounted for 1.5 million deaths. Fluoroquinolone antibacterials, which target DNA gyrase, are critical agents used to halt the progression from multidrug-resistant tuberculosis to extensively resistant disease; however, fluoroquinolone resistance is emerging and new ways to bypass resistance are required. To better explain known differences in fluoroquinolone action, the crystal structures of the WT Mtb DNA gyrase cleavage core and a fluoroquinolone-sensitized mutant were determined in complex with DNA and five fluoroquinolones. The structures, ranging from 2.4- to 2.6-Å resolution, show that the intrinsically low susceptibility of Mtb to fluoroquinolones correlates with a reduction in contacts to the water shell of an associated magnesium ion, which bridges fluoroquinolone-gyrase interactions. Surprisingly, the structural data revealed few differences in fluoroquinolone- enzyme contacts from drugs that have very different activities against Mtb. By contrast, a stability assay using purified components showed a clear relationship between ternary complex reversibility and inhibitory activities reported with cultured cells. Collectively, our data indicate that the stability of fluoroquinolone/DNA interactions is a major determinant of fluoroquinolone activity and that moieties that have been appended to the C7 position of different quinolone scaffolds do not take advantage of specific contacts that might be made with the enzyme. These concepts point to new approaches for developing quinolone-class compounds that have increased potency against Mtb and the ability to overcome resistance.
KW - Antibiotic resistance
KW - Complex stability
KW - Fluoroquinolone
KW - Gyrase
KW - Mycobacterium tuberculosis
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U2 - 10.1073/pnas.1525047113
DO - 10.1073/pnas.1525047113
M3 - Article
C2 - 26792525
AN - SCOPUS:84959422266
VL - 113
SP - 1706
EP - 1713
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 7
ER -