What the study found
The study found that antibacterial drugs inhibit one gyrase activity, DNA decatenation, at lower concentrations than they inhibit gyrase-mediated DNA relaxation or supercoiling in mycobacteria. The authors report that this difference in potency is linked to the topological state of the DNA and its specific interactions with gyrase.
Why the authors say this matters
The authors conclude that the study provides mechanistic insight into how gyrase-targeted antibacterials deprive replicating cells of essential gyrase functions. They also note that most studies focus on DNA cleavage, whereas their work addresses inhibition of gyrase function itself.
What the researchers tested
The researchers examined the effects of moxifloxacin and ciprofloxacin, which are fluoroquinolones, and zoliflodacin, a spiropyrimidinetrione, on three catalytic activities attributed to gyrase in mycobacteria: decatenation of tangled DNA, negative supercoiling of relaxed DNA, and relaxation of positive supercoils. They studied these effects in the context of mycobacterial gyrase, which is the only type II topoisomerase encoded in some species such as Mycobacterium tuberculosis and Mycobacteroides abscessus.
What worked and what didn't
Lower drug concentrations were needed to inhibit intermolecular DNA decatenation than to inhibit the intramolecular DNA relaxation or supercoiling functions of gyrase. The differences in drug potency could not be explained only by the rates of the individual reactions or by the DNA substrates used.
What to keep in mind
The abstract does not describe experimental limitations beyond the scope of the tested drugs and gyrase activities. The findings are limited to the antibacterial agents and mycobacterial gyrase functions studied here.
Key points
- Antibacterial drugs inhibited mycobacterial gyrase decatenation at lower concentrations than relaxation or supercoiling.
- The drugs tested were moxifloxacin, ciprofloxacin, and zoliflodacin.
- The authors say drug potency is influenced by DNA topology and specific DNA-gyrase interactions.
- Differences in potency were not explained solely by reaction rates or DNA substrates.
- The abstract frames the work as mechanistic insight into gyrase inhibition rather than DNA cleavage.
Disclosure
- Research title:
- Mycobacterial gyrase inhibition depends on DNA topology
- Authors:
- Jillian F. Armenia, Neil Osheroff
- Institutions:
- Vanderbilt University
- Publication date:
- 2026-01-27
- OpenAlex record:
- View
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