Journal article
Fluoroquinolones stimulate the DNA cleavage activity of topoisomerase IV by promoting the binding of Mg2+ to the second metal binding site
Biochimica et biophysica acta. General subjects, Vol.1860(3), pp.569-575
03/2016
DOI: 10.1016/j.bbagen.2015.12.019
PMCID: PMC4720527
PMID: 26723176
Abstract
Fluoroquinolones target bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV (Topo IV). Fluoroquinolones trap a topoisomerase–DNA covalent complex as a topoisomerase–fluoroquinolone–DNA ternary complex and ternary complex formation is critical for their cytotoxicity. A divalent metal ion is required for type IIA topoisomerase-catalyzed strand breakage and religation reactions. Recent studies have suggested that type IIA topoisomerases use two metal ions, one structural and one catalytic, to carry out the strand breakage reaction.
We conducted a series of DNA cleavage assays to examine the effects of fluoroquinolones and quinazolinediones on Mg2+-, Mn2+-, or Ca2+-supported DNA cleavage activity of Escherichia coli Topo IV.
In the absence of any drug, 20–30mMMg2+ was required for the maximum levels of the DNA cleavage activity of Topo IV, whereas approximately 1mM of either Mn2+ or Ca2+ was sufficient to support the maximum levels of the DNA cleavage activity of Topo IV. Fluoroquinolones promoted the Topo IV-catalyzed strand breakage reaction at low Mg2+ concentrations where Topo IV alone could not efficiently cleave DNA.
At low Mg2+ concentrations, fluoroquinolones may stimulate the Topo IV-catalyzed strand breakage reaction by promoting Mg2+ binding to metal binding site B through the structural distortion in DNA. As Mg2+ concentration increases, fluoroquinolones may inhibit the religation reaction by either stabilizing Mg2+ at site B or inhibition the binding of Mg2+ to site A. This study provides a molecular basis of how fluoroquinolones stimulate the Topo IV-catalyzed strand breakage reaction by modulating Mg2+ binding.
•Fluoroquinolones promote the binding of Mg2+ to site B to stimulate strand breakage.•Fluoroquinolones may inhibit religation by stabilizing Mg2+ binding at site B.•Quinazolinediones act by the same mechanisms as fluoroquinolones.•Topoisomerase IV cannot complete the catalytic reaction using Ca2+ as a cofactor.
Details
- Title: Subtitle
- Fluoroquinolones stimulate the DNA cleavage activity of topoisomerase IV by promoting the binding of Mg2+ to the second metal binding site
- Creators
- Lisa M Oppegard - Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USAHeidi A Schwanz - Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USATyrell R Towle - Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USARobert J Kerns - Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USAHiroshi Hiasa - Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA
- Resource Type
- Journal article
- Publication Details
- Biochimica et biophysica acta. General subjects, Vol.1860(3), pp.569-575
- DOI
- 10.1016/j.bbagen.2015.12.019
- PMID
- 26723176
- PMCID
- PMC4720527
- NLM abbreviation
- Biochim Biophys Acta Gen Subj
- ISSN
- 0304-4165
- eISSN
- 1872-8006
- Publisher
- Elsevier BV
- Grant note
- DOI: 10.13039/100000002, name: National Institutes of Health, award: R01 AI087671; name: National Institutes of Health Predoctoral Traineeship in Biotechnology, award: T32GM008365; DOI: 10.13039/100005496, name: American Foundation for Pharmaceutical Education; name: American Chemical Society Division of Medicinal Chemistry Predoctoral Fellowship
- Language
- English
- Date published
- 03/2016
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984065324802771
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