Fig. 1

Module organization of epothilone synthase and structures of epothilones A–D. The modular architecture of the six constituent proteins (EpoA–F) is shown in cartoon form. Domain annotation: KS ketosynthase; AT acyltransferase; ACP acyl carrier protein; MT methyltransferase; KR ketoreductase; DH dehydratase; ER enoylreductase; TE thioesterase. The biosynthetic building blocks derived from L-cysteine, S-adenosylmethionine (SAM), acetyl-CoA, (2S)-methylmalonyl-CoA, and malonyl-CoA are highlighted with red lines. Empty circles indicate nonfunctional domains. Epothilones C and D are converted to epothilones A and B, respectively, by EpoK