Targeting the FtsZ Allosteric Binding Site with a Novel Fluorescence Polarization Screen, Cytological and Structural Approaches for Antibacterial Discovery

Bacterial resistance to antibiotics makes previously manageable
infections again disabling and lethal, highlighting the need for new
antibacterial strategies. In this regard, inhibition of the bacterial
division process by targeting key protein FtsZ has been recognized
as an attractive approach for discovering new antibiotics. Binding
of small molecules to the cleft between the N-terminal guanosine triphosphate
(GTP)-binding and the C-terminal subdomains allosterically impairs
the FtsZ function, eventually inhibiting bacterial division. Nonetheless,
the lack of appropriate chemical tools to develop a binding screen
against this site has hampered the discovery of FtsZ antibacterial
inhibitors. Herein, we describe the first competitive binding assay
to identify FtsZ allosteric ligands interacting with the interdomain
cleft, based on the use of specific high-affinity fluorescent probes.
This novel assay, together with phenotypic profiling and X-ray crystallographic
insights, enables the identification and characterization of FtsZ
inhibitors of bacterial division aiming at the discovery of more effective
antibacterials.