Certain dangerous fungal infections like aspergillosis are difficult to treat because current antifungal drugs have significant side effects or the fungi are developing resistance. Scientists have discovered that a specific enzyme called Δ9-fatty acid desaturase, which fungi need to make fats for their cell membranes, has a unique structure different from human cells. This structural difference offers a new opportunity to design antifungal drugs that could kill fungi without harming human cells, potentially providing safer and more effective treatments for serious fungal infections.