Polyketide Bioderivatization Using the Promiscuous Acyltransferase KirCII.

During polyketide biosynthesis, acyltransferases (ATs) are the essential gatekeepers which provide the assembly lines with precursors and thus contribute greatly to structural diversity. Previously, we demonstrated that the discrete AT KirCII from the kirromycin antibiotic pathway accesses nonmalonate extender units. Here, we exploit the promiscuity of KirCII to generate new kirromycins with allyl- and propargyl-side chains in vivo, the latter were utilized as educts for further modification by "click" chemistry.