Fig. 2

Replacing EPOAT4 with the AT domains specific to MMCoA can significantly increase the ratio of epothilone D to epothilone C. a The module 4 AT domain of epothilone PKS (EPOAT4) was replaced with MMCoA-specific AT domains (shown in red). Domain annotation: KAL, KS to AT linker; PAL1, non-conserved N-terminal region in the post-AT linker; PAL2, conserved C-terminal region in the post-AT linker. b Epothilone production and epothilone D proportion from six engineered EPOAT4-swapped mutant strains (MMR2048, MMR2049, MMR2017, MMR2016, MMR2018, and MMR2012). c Extracts from the parental and mutant strains were analysed by HPLC. 3 represents epothilone C, 4 represents epothilone D. Statistical analysis was performed using Student’s t-test (**p < 0.01, ***p < 0.001). Error bars represent one standard deviation from three biological replicates (n = 3)