Biocombinatorial Synthesis of Novel Lipopeptides by COM Domain-Mediated Reprogramming of the Plipastatin NRPS Complex.

Both donors and acceptors of communication-mediating (COM) domains are essential for coordinating intermolecular communication within nonribosomal peptides synthetases (NRPSs) complexes. Different sets of COM domains provide selectivity， allowing NRPSs to utilize different natural biosynthetic templates. In this study， novel lipopeptides were synthesized by reprogramming the plipastatin biosynthetic machinery. A Thr-to-Asp point mutation was sufficient to shift the selectivity of the donor COM domain of ppsB toward that of ppsD. Deletion and/or interchangeability established donor and acceptor function. Variations in acceptor COM domain did not result in novel product formation in the presence of its partner donor， whereas plipastatin formation was completely abrogated by altering donor modules. Five novel lipopeptides (cyclic pentapeptide， linear hexapeptide， nonapeptide， heptapeptide， and cyclic octapeptide) were identified and verified by high-resolution LC-ESI-MS/MS. In addition， we demonstrated the potential to generate novel strains with the antimicrobial activity by selecting compatible COM domains， and the novel lipopeptides exhibited antimicrobial activity against five of the fungal species at a contention of 31.25-125 μg/ml.