Tunicamycin 15:1 is a mixture of tunicamycin structural isomers that contain a 15-carbon N-acyl chain with variable branching patterns. The N-acyl chain incorporated into tunicamycins, like tunicamycin 15:1, is derived from the same pool of cellular branched-chain fatty acids (BCFAs) in Streptomyces and directly impacts the biological activity of each individual tunicamycin variant. Purified tunicamycin 15:1 with iso, anteiso, or a mixture of iso and anteiso branching configurations inhibit bacterial phospho-MurNAc-pentapeptide transferase (MraY) with IC50 values of 0.05, 0.36, and 0.09 μM, respectively.
