A Chemical Disruptor of the ClpX Chaperone Complex Attenuates the Virulence of Multidrug-Resistant Staphylococcus aureus.

The Staphylococcus aureus ClpXP protease is an important regulator of cell homeostasis and virulence. We utilized a high-throughput screen against the ClpXP complex and identified a specific inhibitor of the ClpX chaperone that disrupts its oligomeric state. Synthesis of 34 derivatives revealed that the molecular scaffold is restrictive for diversification, with only minor changes tolerated. Subsequent analysis of the most active compound revealed strong attenuation of S. aureus toxin production, which was quantified with a customized MS-based assay platform. Transcriptome and whole-proteome studies further confirmed the global reduction of virulence and revealed characteristic signatures of protein expression in the compound-treated cells. Although these partially matched the pattern of ClpX knockout cells, further depletion of toxins was observed, leading to the intriguing perspective that additional virulence pathways may be directly or indirectly addressed by the small molecule.