Highlights
•  Structures of DPAGT1 with UDP-GlcNAc and tunicamycin reveal mechanisms of catalysis •  DPAGT1 mutations in patients with glycosylation disorders modulate DPAGT1 activity •  Structures, kinetics and biosynthesis reveal role of lipid in tunicamycin •  Lipid-altered, tunicamycin analogues give non-toxic antibiotics against TB

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