Polyketides are natural products with anticancer, immunosuppressive, antimicrobial, and antiparasitic activities. The polyketide antifungal ansatrienin A is produced by Streptomyces collinus with coenzyme A–activated cyclohexanecarboxylic acid (CHC-CoA) as an intermediate in its synthesis. Now Cropp et al. have identified four CHC-CoA biosynthetic genes in S. collinus. By expressing the CHC-CoA biosynthetic gene cluster in a strain used to produce another polyketide, the antiparasitic doramectin, they were able to produce this valuable compound without the usual CHC supplementation to the fermentation. The CHC-CoA biosynthetic gene cluster has potential for directed biosynthesis in other important polyketide organisms (see p. 980).