FenF: Servicing the Mycosubtilin Synthetase Assembly Line in trans

AT your service. We report the expression and characterization of FenF from mycosubtilin biosynthesis. This work represents the first kinetic and selectivity studies performed on an in trans AT domain servicing a polyketide synthase (PKS), and revealed a strong acyl‐group specificity and broad promiscuity toward substrate carrier proteins. The lack of specificity in FenF‐mediated malonyl transfer suggests that this protein might prove a powerful tool for combinatorial biosynthesis.