Tunicamycin, a mixture of homologous nucleosides, is a N-acetylglucosamine containing antibiotic found in Streptomyces lysosuperijkus which inhibits protein glycosylation. Tunicamycin causes accumulation of unfolded proteins in cell endoplasmic
reticulum (ER) and induces ER stress, and causes blocking of DNA
synthesis and cell cycle arrest in G1 phase. Tunicamycin inhibits gram-positive bacteria, yeasts, fungi, and viruses and has anti-cancer activity.