Compound Z247611722 Exhibits Antifungal Activity by Inhibiting Serine Palmitoyltransferase.

The global rise in fungal infections, driven by expanding at-risk populations and growing antifungal resistance, highlights the need for new therapies. However, the current antifungal arsenal remains limited and emerging resistance reduces treatment efficacy. Through high-throughput screening of 20,000 drug-like compounds, we identified Z56812898, a benzamide linked to a bicyclic pyrimidine-pyran trione with novel antifungal activity. Guided by this hit, we discovered a structural analog with improved antifungal potency, Z247611722. This fungicidal compound has novel antifungal activity against multiple Candida species and fluconazole-resistant isolates. Chemogenomic, metabolomic, and phenotypic analyses revealed that Z247611722 disrupts sphingolipid biosynthesis by targeting serine palmitoyltransferase (SPT). The mode of action was confirmed by experimental evolution, yielding a resistant strain with a non-synonymous mutation in the SPT-encoding gene, LCB2. Structural modelling localized this alanine-to-proline substitution adjacent to the catalytic cavity, where it could alter the dynamics and conformation of the binding pocket and impair compound accommodation. Importantly, Z247611722 demonstrates in vivo efficacy in an invertebrate model of C. albicans infection. These findings validate SPT as a promising target and introduce a structurally distinct sphingolipid biosynthesis inhibitor with therapeutic potential.