Activates two amino acids and incorporate a D-ornithine from its second active site into bacitracin. L-ornithine = D-ornithine Binds 2 phosphopantetheines covalently. Antibiotic biosynthesis; bacitracin biosynthesis. Large multienzyme complex of BA1, BA2 and BA3. Consists of two modules with a C-terminal epimerization domain. Each module incorporates one amino acid into the peptide product and can be further subdivided into domains responsible for substrate adenylation, thiolation, condensation (not for the initiation module), and epimerization (optional), and N methylation (optional). Bacitracin is a mixture of at least ten cyclic dodecapeptides, that differ by one or two amino acids. The most abundant is bacitracin A, a branched cyclic dodecapeptide. It contains an N-terminal linear pentapeptide moiety (Ile-Cys-Leu-D-Glu-Ile) with an isoleucine-cysteine thiazoline condensation product and a C-terminal heptapeptide ring (Lys-D-Orn-Ile-D-Phe-His-D-Asp-Asn), in which the free alpha-carboxy group of the C-terminal Asn is bound to the epsilon-amino group of Lys. Belongs to the ATP-dependent AMP-binding enzyme family.