Mechanism of Action of the Cell-Division Inhibitor PCI 90723: Modulation of FtsZ Assembly Cooperativity

摘要

The cooperative assembly of FtsZ, the prokaryotic homologue of tubulin, plays an essential role in cell division. FtsZ is a potential drug target, as illustrated by the small-molecule cell-cycle inhibitor and antibacterial agent PC 190723 that targets FtsZ. We demonstrate that PC 190723 negatively modulates Staphylococcus aureus FtsZ polymerization cooperativity as reflected in polymerization at lower concentrations without a denned critical concentration. The crystal structure of the S. aureus FtsZPC190723 complex shows a domain movement that would stabilize the FtsZ protofilament over the monomeric state, with the conformational change mediated from the GTP-binding site to the C-terminal domain via helix 7. Together, the results reveal the molecular mechanism of FtsZ modulation by PC 190723 and a conformational switch to the high-affinity state that enables polymer assembly.