What the study found
The study found that antibacterial drugs inhibited one gyrase function, intermolecular DNA decatenation, at lower concentrations than they inhibited intramolecular DNA relaxation or negative supercoiling. The results suggest that inhibition of mycobacterial gyrase is influenced by the DNA’s topological state and by how the DNA interacts with gyrase.
Why the authors say this matters
The authors conclude that the study provides mechanistic insight into how antibacterials rob replicating cells of essential gyrase functions. The study suggests this is relevant because, in some mycobacterial species, gyrase is the only type II topoisomerase target available to these drugs.
What the researchers tested
The researchers examined the effects of moxifloxacin and ciprofloxacin, both fluoroquinolones, and zoliflodacin, a spiropyrimidinetrione, on three catalytic activities of mycobacterial gyrase. These activities were decatenation of tangled DNA, negative supercoiling of relaxed DNA, and relaxation of positive supercoils.
What worked and what didn't
Under all tested conditions, lower antibacterial concentrations were needed to inhibit DNA decatenation than to inhibit DNA relaxation or supercoiling. The abstract says that differences in 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 in detail. It also focuses on in vitro gyrase activities and does not provide direct clinical outcomes or cell-based comparisons beyond the general statement that gyrase functions are essential in replicating cells.
Key points
- Mycobacterial gyrase was inhibited more easily during DNA decatenation than during DNA relaxation or supercoiling.
- Moxifloxacin, ciprofloxacin, and zoliflodacin were tested against three gyrase activities.
- The findings suggest that DNA topology and DNA-gyrase interactions affect antibacterial potency.
- The abstract says reaction rates and DNA substrate choice alone did not explain the potency differences.
- The authors frame the work as mechanistic insight into loss of essential gyrase function.
Disclosure
- Research title:
- Mycobacterial gyrase inhibition varies with DNA topology
- Authors:
- Jillian F. Armenia, Neil Osheroff
- Institutions:
- Vanderbilt University, Vanderbilt University
- Publication date:
- 2026-01-27
- OpenAlex record:
- View
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