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The image is of an organelle containing 10–100 associated 2.5 MDa NRPS-PKS mega-complexes from B. subtilis (Straight et al., 2007). The erythromycin pathway is shown from Saccharopolyspora erythraea NRRL 2338 and echinomycin pathway from Streptomyces lasaliensis. For erythromycin, chemical groups added by post-assembly-line tailoring enzymes (two P450s and two glycosyltransferases) are shown in red. A, adenylation; T, thiolation; C, condensation; E, epimerization; MT, methyltransferase; TE, thioesterase; AT, acyltransferase; KS, ketosynthase; KR, ketoreductase; DH, dehydratase; ER, enoylreductase. Bacteriochlorophyll (bottom left) is incorporated into light harvesting complexes. FeMoCo (bottom right) is produced by a metabolic pathway and incorporated into nitrogenase (image from Noodleman et al. [2004]). All images reproduced with permission.