Fig. 2.

Gene and module organizations of avermectin and milbemycin biosynthetic gene clusters. a Milbemycin PKS in S. bingchenggensis BCW-1. The PKS genes (milA1, milA2, milA3, and milA4) for milbemycin biosynthesis were indicated with yellow. b Avermectin PKS in S. avermitilis SA-01. The PKS genes (aveA1, aveA2, aveA3, and aveA4) for the biosynthesis of the avermectin core skeleton were shown with green. The aveD gene that was engineered in this study was shown with red. Empty circles indicate nonfunctional domains