Structure-Guided Design, Synthesis, and Antivirulence Assessment of Covalent Sortase A Inhibitors.

Sortase A (SrtA) is a membrane-associated cysteine transpeptidase required for bacterial virulence regulation and anchors surface proteins to cell wall, thereby assisting biofilm formation. SrtA is targeted in antivirulence treatments against Gram-positive bacterial infections. However, the development of potent small-molecule SrtA inhibitors is constrained owing to the limited understanding of the mode of action of inhibitors in the SrtA binding pocket. Herein, we designed and synthesized a novel class of covalent SrtA inhibitors based on the binding mode detailed in the X-ray crystal structure of the / SrtA complex. analog exhibited 2-fold increased inhibitory activity on SrtA and showed superior inhibitory effects on biofilm formation . protected larvae frominfections while minimally attenuating staphylococcal growth . Our study indicates that the covalent SrtA inhibitor is an antivirulence agent that is effective againstinfections.