1 research outputs found
Oxabicyclooctane-Linked Novel Bacterial Topoisomerase Inhibitors as Broad Spectrum Antibacterial Agents
Bacterial resistance is eroding the
clinical utility of existing
antibiotics necessitating the discovery of new agents. Bacterial type
II topoisomerase is a clinically validated, highly effective, and
proven drug target. This target is amenable to inhibition by diverse
classes of inhibitors with alternative and distinct binding sites
to quinolone antibiotics, thus enabling the development of agents
that lack cross-resistance to quinolones. Described here are novel
bacterial topoisomerase inhibitors (NBTIs), which are a new class
of gyrase and topo IV inhibitors and consist of three distinct structural
moieties. The substitution of the linker moiety led to discovery of
potent broad-spectrum NBTIs with reduced off-target activity (hERG
IC<sub>50</sub> > 18 μM) and improved physical properties.
AM8191
is bactericidal and selectively inhibits DNA synthesis and <i>Staphylococcus aureus</i> gyrase (IC<sub>50</sub> = 1.02 μM)
and topo IV (IC<sub>50</sub> = 10.4 μM). AM8191 showed parenteral
and oral efficacy (ED<sub>50</sub>) at less than 2.5 mg/kg doses in
a <i>S. aureus</i> murine infection model. A cocrystal structure
of AM8191 bound to <i>S. aureus</i> DNA-gyrase showed binding
interactions similar to that reported for GSK299423, displaying a
key contact of Asp83 with the basic amine at position-7 of the linker