Architecture and domain organization of ierative type I PKSs found in enediyne gene clusters: (A) the enediyne PKSE and its relationship with PUFA synthase and (B) PKS for the aromatic polyketide moieties of enediynes and its comparison with orsellinic acid synthase AviM. ACP, acyl carrier protein, AT, acyl transferase; DH, dehydratase; KR, ketoreductase; KS, ketosynthase; PPTase, phosphopantetheinyl transferase.