confers_resistance_to_drug_class confers_resistance_to_drug_class echinocandin antibiotic antifungal resistant fungal C-5 sterol desaturase echinocandin resistant fungal C-5 sterol desaturase ARO:3009625 antibiotic_resistance C-5 sterol desaturase is encoded by ERG3 and is an ER-membrane localized enzyme that catalyzes the introduction of a C-5,6 double bond into episterol, as part of the late ergosterol biosynthesis pathway in fungi. Under normal physiological conditions, Erg3 plays an essential role in channeling sterol intermediates toward ergosterol, the primary sterol of fungal membranes that maintains membrane fluidity, integrity, and the function of membrane-associated proteins.