Novel and Structurally Diversified Bacterial DNA Gyrase Inhibitors Discovered through a Fluorescence-Based High-Throughput Screening Assay

Bacterial DNA gyrase, a type IIA
DNA topoisomerase that plays an
essential role in bacterial DNA replication and transcription, is
a clinically validated target for discovering and developing new antibiotics.
In this article, based on a supercoiling-dependent fluorescence quenching
(SDFQ) method, we developed a high-throughput screening (HTS) assay
to identify inhibitors targeting bacterial DNA gyrase and screened
the National Institutes of Health’s Molecular Libraries Small
Molecule Repository library containing 370,620 compounds in which
2891 potential gyrase inhibitors have been identified. According to
these screening results, we acquired 235 compounds to analyze their
inhibition activities against bacterial DNA gyrase using gel- and
SDFQ-based DNA gyrase inhibition assays and discovered 155 new bacterial
DNA gyrase inhibitors with a wide structural diversity. Several of
them have potent antibacterial activities. These newly discovered
gyrase inhibitors include several DNA gyrase poisons that stabilize
the gyrase-DNA cleavage complexes and provide new chemical scaffolds
for the design and synthesis of bacterial DNA gyrase inhibitors that
may be used to combat multidrug-resistant bacterial pathogens. Additionally,
this HTS assay can be applied to screen inhibitors against other DNA
topoisomerases.