The <i>Saccharomyces</i> killer toxin K62 is a protein of the aerolysin family

Pore-forming toxins are potent biological weapons used across nature, from virulence factors to immune defense proteins. This study identifies K62, a little-known antifungal toxin produced by a wild yeast, as a structural and functional relative of the aerolysin family, which is well-known for forming damaging pores in cell membranes. Using structure prediction, molecular simulations, and biochemical analysis, we show that K62 assembles into large, stable pore-like complexes. Remarkably, K62 is just one member of a large and previously unrecognized family of similar toxin-like proteins found in fungi, plants, and bacteria, including pathogens that affect humans and crops. These findings uncover an unexpected evolutionary link across kingdoms, suggesting that pore-forming toxins may play a widespread role in fungal pathogenesis and microbial warfare. This work lays the foundation for understanding a new group of antifungal molecules and their potential impacts on health, agriculture, and microbial ecology.