TunR1 is an antibiotic and derivative of tunicamycin .1It is active againstB. subtilis(MIC = 0.3 μg ml) and increases the efficacy of the β-lactam antibiotics oxacillin , methicillin , and penicillin G againstB. subtiliswhen used at a concentration of 0.4 μg ml. TunR1 (5 μg ml) is cytotoxic to MDA-MB-231 breast cancer cells and non-cancerous CHO cells. Unlike tunicamycin, TunR1 does not inhibit glycosylation in a protein N-glycosylation assay. 1.Price, N.P., Hartman, T.M., Li, J., et al.Modified tunicamycins with reduced eukaryotic toxicity that enhance the antibacterial activity of β-lactamsJ. Antibiot. (Tokyo)70(11)1070-1077(2017)