P61G11

Unsaturated fatty acids (UFAs) are essential for the membrane function in most bacteria. In Helicobacter pylori (H. pylori), a gastric pathogen, UFA biosynthesis depends on the bifunctional dehydrogenase/isomerase FabX, a promising target against H. pylori. Herein, we report the first FabX inhibitor, P61G11 (compound 1, IC₅₀ = 3.7 ± 0.2 μM), identified via high-throughput screening and featuring a 1,3,4-thiadiazole sulfonamide scaffold. The costructure of FabX-1 reveals occupancy of the L-shaped substrate-binding tunnel via hydrophobic interactions and hydrogen bonds. Structure-based optimization led to more potent derivatives, among which compound 47 showed potent inhibition (IC₅₀ = 0.128 ± 0.002 μM), representing a 29-fold improvement. Compound 47 also demonstrated strong in vitro antibacterial activity (MIC = 0.5-1 μg/mL), when combined with membrane permeabilizers, efflux pump inhibitors, and clarithromycin, and exhibited narrow-spectrum efficacy against H. pylori, providing a novel strategy for anti-H. pylori therapy.