Use of protein-tethered substrates by 2OG-dependent oxygenases in antibiotic biosynthesis. (A) SyrP-catalysed formation of a 3-hydroxyaspartyl group and (B) SyrB2-dependent synthesis of a 3-chlorothreonyl group in syringomycin E synthesis. (C) CytC3 generation of the mono- or dichloro l-2-aminobutyryl group in cytotrienin synthesis. (D) Trichlorination of leucine by BarB1 and BarB2 to make barbamide. (E) CmaB- or KtzD-dependent hydroxylation of isoleucyl groups for subsequent cyclization to coronamic acids. (F) CurA chlorination of a 3-hydroxy-3-methylglutaryl group as part of curacin A synthesis. (G) KthP halogenation of a piperazyl group during formation of kutznerides. (H) Hydroxylation of a histidyl group during synthesis of bleomycin, tallysomycin and zorbamycin (yellow highlight is a single bond in the case of zorbamycin).